BACKGROUND

[0001] Field of the DISCLOSURE

[0002] The present disclosure relates to a photochromic molecule, uses of said molecule, a method of preparing a film comprising said molecule, a film prepared using said molecule, a device comprising such molecule, and a method for synthesis of said molecule.

DESCRIPTION OF THE RELATED ART

[0003] The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

[0004] Transparent displays typically have low contrast when information is displayed, especially if the light in the surrounding is bright. For example, in a bright environment, there is a high amount of reflected light and the contrast of a displayed picture is reduced. Therefore, there is a need for increasing contrast of displays while maintaining transparency of displays. Furthermore, there is the need to provide means for enhanced two-dimensional and three-dimensional displays, such as enhanced dyes. Moreover, there is a need to provide photochromic dyes that are characterized by fast color switching. There is also the need to provide means for enhanced products for the space projection field having a high image quality, such as means for virtual reality.

SUMMARY

[0005] In the following, the elements of the invention will be described. These elements are listed with specific embodiments, however, it should be understood that they may be combined in any manner and in any number to create additional embodiments. The variously described examples and preferred embodiments should not be construed to limit the present invention to only the explicitly described embodiments. This description should be understood to support and encompass embodiments which combine two or more of the explicitly described embodiments or which combine the one or more of the explicitly described embodiments with any number of the disclosed and/or preferred elements. Furthermore, any permutations and combinations of all described elements in this application should be considered disclosed by the description of the present application unless the context indicates otherwise.

[0006] The present disclosure provides a molecule represented by any one of formulae 1-4 wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C3-C10 cycloalkyl, Ci- C3 haloalkyl, hydroxyl, -OR ¹³ , -N(R ¹⁴ )2, e.g. -N(CH3)2 or -NH2, -COOR ¹⁵ , -COOH, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups; wherein, preferably, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are, at each occurrence, independently selected from the group consisting of hydrogen, halogen, -OR ¹³ , - N(R ¹⁴ ) ₂ , -COOR ¹⁵ , -COOH, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹³ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁴ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups; R ¹⁵ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^a is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, heterocyclyl, heteroaryl and aryl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted;

Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , and Ar ⁸ are, at each occurrence, independently selected from aryl, preferably phenyl, and heteroaryl, wherein each of said aryl and heteroaryl is optionally substituted with one to four R ^b groups, wherein, preferably, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , and Ar ⁸ are, at each occurrence, independently selected from , wherein

D is an electron donating unit, preferably selected from halogen, -OR ¹⁶ , -N(R ¹⁷ )2, heterocyclyl, e.g. piperidinyl, pyrrolidinyl, morpholinyl, and heteroaryl, e.g. indolyl, indolinyl, thiophenyl, quinolinyl;

R ¹⁶ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁷ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^b is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, aryl, heterocyclyl, e.g. piperidinyl, pyrrolidinyl, morpholinyl, and heteroaryl, e.g. indolyl, indolinyl, thiophenyl, quinolinyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted. [0007] The present disclosure provides the use of a molecule according to the present disclosure in a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses.

[0008] The present disclosure provides the use of a molecule according to the present disclosure for increasing contrast of a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses.

[0009] The present disclosure provides the use of a molecule according to the present disclosure and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162, for preparing a film comprising a matrix.

[0010] The present disclosure provides a method of preparing a film comprising a molecule according to the present disclosure, and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162, comprising the following steps: i) providing a molecule according to the present disclosure, and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162, ii) combining said molecule with a carrier, preferably a matrix, wherein, preferably, said combining comprises impregnating said carrier with said molecule, codepositing said molecule with said carrier, embedding said molecule into said carrier, and/or coating said carrier with said molecule.

[0011] The present disclosure provides a film prepared using a molecule according to the present disclosure, optionally comprising a carrier, preferably a matrix.

[0012] The present disclosure provides a device, comprising a molecule according to the present disclosure, and/or comprising a film according to the present disclosure, wherein said device is optionally an electronic device, wherein, preferably, said device is a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses. [0013] The present disclosure provides a method for synthesis of a molecule according to the present disclosure, comprising steps I and II of any one of the following schemes I, II, III, or IV: wherein, preferably, step I comprises converting a substituted arylketone into a substituted propynol using an R-substituted organometallic reagent, preferably R-substituted lithium acetylide, more preferably a THF solution of R-substituted lithium acetylide, even more preferably an anhydrous THF solution of R-substituted lithium acetylide prepared from n-BuLi and R-substituted acetylene, e.g. at about 0°C in an inert atmosphere, and/or step II comprises cyclisation, preferably using an acidic catalyst and a solvent under reflux, more preferably using acidic AI2O3, or pyridinium p-toluenesulfonate (PPTS) with trimethyl orthoformate, in a solvent under reflux, e.g. toluene at a temperature of about 110 °C.

[0014] The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

[0016] Figure 1 shows that dyes of the present disclosure allow for providing products having high costumer value. To improve the contrast ratio of a product, transmission control by light projection is necessary. Fast response photochromic dyes of the present disclosure are compatible for video images.

[0017] Figure 2 shows the mechanism of photochromic dyes of the present disclosure. When a photochromic dye is exposed to UV radiation, a chemical bond is broken such as 2NPhNP in the shown exemplary dye, as indicated by the dotted arrow. The molecule then rearranges into a species that absorbs at longer wavelengths in the visible region, causing the appearance of color (coloring). The process is thermally reversed and, after a certain time (ks to ms) depending on the temperature and the height of the energy barrier between the two isomers, the ring closure process is completed, and the colors disappear (fading).

[0018] Figure 3 shows coloring and fading response times. A) The coloring and fading response times were determined by 90% thresholds. B) Effect of UV-intensity on the coloring response time for different samples of two different dyes. The UV-intensity strongly affects the switching time. Coloring response time is approximately proportional to the 1/UV intensity. C) Effect of UV-intensity on the fading response time for different samples of two different dyes. The fading response time is independent on the UV-intensity used for the coloring.

[0019] Figure 4 shows visible light spectra of exemplary dyes of the present disclosure. The spectra were recorded in the response time measurement setup during excitation by UV. All dyes were absorbing in the visible range showing coloring going from yellow to dark violet/brown.

[0020] Figure 5 gives an overview of the experimental results of exemplary dyes of the present disclosure in solution and in matrix. Coloring response times are in a narrow range of 0.1s to 0.4s for 0.5 W/cm ² UV-intensity (values measured at 1.4 W/cm ² need to be multiplied by a factor of approx. 3 when compared to the values measured at 0.5 W/cm ² ). Fastest coloring dyes are TPC-0024, UTAD Np, RES-006, RES-007, Strom Purple, and Solar Yellow. Fading response times span a much larger range of 0. Is to more than 100s, all measured at room temperature. Fastest fading dyes at room temperature are UTAD Np, RES- 004, RES-006, RES-007, RES-011, and RES-042. Comparable low relative transmission in the colored state, that is good contrast in the device, was observed for RES-004, RES-006, Strom Purple, Plum Red, Sea Green, RES-11, RES LS-43, and RES-042. Good overall performance is observed for RES-004, RES-006, and RES-042. Low coloring and fading times were retained in matrix. The molecules of the disclosure have highly advantageous coloring and fading times, even when embedded in a matrix.

[0021] Figure 6 shows different matrices for embedding a dye of the present disclosure. There are various approaches for embedding a photochromic dye in a matrix, such as using 1) a (co-)polymer base, such as a TPU (thermoplastic polyurethane), tri-block acrylic-based polymer comprising poly(methyl methacrylate) (PMMA) and poly(-butyl acrylate) (PBA), as well as Styrenic Block Copolymer (SEBS), 2) a PIMs (polymer of intrinsic microporosity) base, such as PTMSP (poly(trimethylsilyl)propyne), or 3) an inorganic-organic hybrid base, such as a SiO2-ethylenoxy hydrid, TEOS-GPTMS (tetraethyl orthosilicate and 3- (glycidoxypropyl)methyldiethoxysilane), Acier HC (hardcoat). Advantageously, the molecules according to the present disclosure can be incorporated into various matrices and maintain the advantageous properties that they have in solution, such as fast coloring and fading responses.

[0022] Figure 7 shows an improvement of TPU rubber film impregnation. Homogeneous films with high absorption were obtained. The methodology for impregnation resulted in homogeneous films with high absorption.

[0023] Figure 8 shows various PC responses. A) The impact of different dipping times on PC response was investigated. Since the impact of longer dipping times was very low, a dipping time of 15 min is considered sufficient for impregnation. B) The TPU Elastollan® matrix was softened by addition of GPTMS and compared to matrix without GPTMS. The addition of 10 wt% GPTMS led to an improvement in the PC response of the TPU films, namely stronger absorption/coloring depth, mostly a faster response time, and slower fading times.

[0024] Figure 9 shows insertion of elastomers in a SiCE sol-gel (based on TEOS monomers) to introduce free mobility for PC dye switching. Photochromic behavior was measured with following outcome: A higher amount of GPTMS in TEOS showed a slower coloring (~4x) but also a faster fading (~5x).

[0025] Figure 10 shows embedding of dyes of the present disclosure with Acier Hard Coat.

A) shows bonding of organic compounds and inorganic particles within the hybrid hard coating. B) shows the transmission over time. The film showed low absorption combined with extremely slow coloring and fading times. Also a strong hysteresis is found.

[0026] Figure 11 shows that polymers of intrinsic microporosity (PIMs) can be used to embed photochromic dyes of the present disclosure (A). (B) An investigation of response time of a dye in a matrix. UTAD dye was analyzed in an exemplary PTMSP matrix on glass. The microporosity of the matrix allows dye switching in the matrix.

[0027] Figure 12 shows a comparison of different matrices for photochromic dyes. Fad. indicates the time of the return to the transparent state, HysFad is considering the hysteresis seen during the colored stage. This means that in some cases the transparency does not return to its initial value after the coloration.

[0028] Figure 13 shows exemplary results obtained for TCP33 in the UV region (left) and visible region (right) are shown in Figure 13.

[0029] Figure 14 shows A) coloring response time being affected by the UV pulse intensity,

B) minimum transmission increasing with higher temperature and coloring response time slightly decreasing with higher temperature for TPC24 in TPU, C) minimum transmission significantly decreasing with increasing concentration of dye in solution.

[0030] Figure 15 shows coloring and fading response times as a function of temperature.

A) shows an evaluation of an exemplary dye (UTAD) in different matrices. With regard to coloring response as a function of temperature, different coloring responses at two different temperature regions were observed for all combinations, namely a strong decrease up to approx. 0°C and a slower curved decrease above 0°C. An initial fast decrease was not observed for PDMS. T _g of PDMS, Resamine®, and Elastollan® is -123 °C, -34 °C, and - 30 °C, respectively. With regard to fading response as a function of temperature, different fading responses at 2 different temperature regions was observed for all dyes, namely a strong decrease up to approx. 10°C and a slower decrease above 10°C.

B) Temperature dependence of different dyes in TPU was also investigated. For example, Resamine® (exemplary TPU polymer) was used as a standard matrix for embedding a dye, preferably creating a free standing film. Highly performing dyes (e.g. RES-006, RES-033, RES-034, RES-042) were investigated and compared with UTAD dye. With regard to coloring response as a function of temperature in polymer matrix (Resamine®), varying coloring responses at three different temperature regions were observed; a rapid decrease up to approx. -10°C; then a plateau (with exception RES-34); and a slower decrease above 20°C. The strongest variations between dyes were observed at higher temperatures. With regard to fading response as a function of temperature, a different coloring response at 2 different temperature regions was observed for all dyes; a rapid decrease up to approx. 20°C and a slightly reduced decrease above 20°C. Two temperature regions ranges were also observed in the transmission.

[0031] Figure 16 shows a dye characterization. Exemplary dye RES-042 was analyzed in solution.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.

[0033] As discussed above, the present disclosure provides a molecule represented by any one of formulae 1-4 wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are, at each occurrence, independently selected from the group consisting of hydrogen, halogen, Ci-Cio alkyl, C3-C10 cycloalkyl, Ci- C3 haloalkyl, hydroxyl, -OR ¹³ , -N(R ¹⁴ )2, e.g. -N(CH3)2 or -NH2, -COOR ¹⁵ , -COOH, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups; wherein, preferably, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are, at each occurrence, independently selected from the group consisting of hydrogen, halogen, -OR ¹³ , - N(R ¹⁴ ) ₂ , -COOR ¹⁵ , -COOH, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹³ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁴ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁵ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^a is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, heterocyclyl, heteroaryl and aryl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted;

Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , and Ar ⁸ are, at each occurrence, independently selected from aryl, preferably phenyl, and heteroaryl, wherein each of said aryl and heteroaryl is optionally substituted with one to four R ^b groups, wherein, preferably, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , and Ar ⁸ are, at each occurrence, independently selected from , wherein

D is an electron donating unit, preferably selected from halogen, -OR ¹⁶ , -N(R ¹⁷ ) ₂ , heterocyclyl, e.g. piperidinyl, pyrrolidinyl, morpholinyl, and heteroaryl, e.g. indolyl, indolinyl, thiophenyl, quinolinyl;

R ¹⁶ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups; R ¹⁷ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^b is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, aryl, heterocyclyl, e.g. piperidinyl, pyrrolidinyl, morpholinyl, and heteroaryl, e.g. indolyl, indolinyl, thiophenyl, quinolinyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted.

[0034] In one embodiment, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , and Ar ⁸ are, at each occurrence, independently selected from the group consisting of wherein

X is hydrogen or halogen, preferably F, Cl, or Br;

R ¹⁸ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁹ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^a is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, heterocyclyl, heteroaryl and aryl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted.

wherein

R ¹³ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁴ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ¹⁵ is, at each occurrence, independently selected from hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, aryl, heteroaryl and heterocyclyl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted with one to four R ^a groups;

R ^a is, at each occurrence, independently selected from the group consisting of hydrogen, halogen, C1-C10 alkyl, C1-C10 alkoxy, aryloxy, C1-C3 haloalkyl, hydroxyl, C1-C3 alkylhydroxyl, C3-C10 cycloalkyl, heterocyclyl, heteroaryl and aryl, wherein each of said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl is optionally substituted.

[0036] In one embodiment, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are, at each occurrence, independently selected from the group consisting of hydrogen, halogen, -OMe, -

wherein, preferably, the molecule is selected from any one of RES-006 and RES-042.

Ar ² is not phenyl substituted with piperidinyl; and/or if R ⁴ is -N(CH3)2, R ⁵ is -COOPr, R ⁶ is hydrogen, and Ar ³ is unsubstituted phenyl, then Ar ⁴ is not phenyl substituted with piperidinyl; and/or if R ¹ is hydrogen, R ² is morpholinyl, R ³ is hydrogen, and Ar ¹ is unsubstituted phenyl, then Ar ² is not unsubstituted phenyl.

[0002] As discussed above, the present disclosure provides the use of a molecule according to the present disclosure in a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses.

[0003] As discussed above, the present disclosure provides the use of a molecule according to the present disclosure for increasing contrast of a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses. [0004] As discussed above, the present disclosure provides the use of a molecule according to the present disclosure and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162, for preparing a film comprising a matrix.

[0005] As discussed above, the present disclosure provides a method of preparing a film comprising a molecule according to the present disclosure, and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2- 110, RE SA 2-51, RE SA 2-162, comprising the following steps: i) providing a molecule according to the present disclosure, and/or a molecule selected from TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162, ii) combining said molecule with a carrier, preferably a matrix, wherein, preferably, said combining comprises impregnating said carrier with said molecule, codepositing said molecule with said carrier, embedding said molecule into said carrier, and/or coating said carrier with said molecule. [0043] In one embodiment, said matrix is selected from the group consisting of copolymer bases, such as TPUs, SEBS, PMMA-PnBA, PIMs bases, such as PTMSP, inorganic-organic hybrid bases, such as SiO ₂ -ethylenoxy hybrid, TEOS-GPTMS, Acier HC, polyurethane materials, e.g. Elastollan®, and PDMS, more preferably Elastollan® and PDMS.

[0044] In one embodiment, said molecule is RES-006 and/or RES-042 and said matrix is PDMS and/or Elastollan®.

[0045] As discussed above, the present disclosure provides a film prepared using a molecule according to the present disclosure, optionally comprising a carrier, preferably a matrix.

[0046] The present disclosure provides a film comprising a molecule according to the present disclosure, optionally comprising a carrier, preferably a matrix.

[0047] In one embodiment, said matrix is selected from the group consisting of copolymer bases, such as TPUs, SEBS, PMMA-PnBA, PIMs bases, such as PTMSP, inorganic-organic hybrid bases, such as SiCE-ethylenoxy hybrid, TEOS-GPTMS, Acier HC, polyurethane materials, e.g. Elastollan®, and PDMS, more preferably Elastollan® and PDMS.

[0048] As discussed above, the present disclosure provides a device, comprising a molecule according to the present disclosure, and/or comprising a film according to the present disclosure, wherein said device is optionally an electronic device, wherein, preferably, said device is a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses.

[0049] As discussed above, the present disclosure provides a method for synthesis of a molecule according to the present disclosure, comprising steps I and II of any one of the following schemes I, II, III, or IV :

wherein, preferably, step I comprises converting a substituted arylketone into a substituted propynol using an R-substituted organometallic reagent, preferably R-substituted lithium acetylide, more preferably a THF solution of R-substituted lithium acetylide, even more preferably an anhydrous THF solution of R-substituted lithium acetylide prepared from n-BuLi and R-substituted acetylene, e.g. at about 0°C in an inert atmosphere, and/or step II comprises cyclisation, preferably using an acidic catalyst and a solvent under reflux, more preferably using acidic AI ₂ O ₃ , or pyridinium p-toluenesulfonate (PPTS) with trimethyl orthoformate, in a solvent under reflux, e.g. toluene at a temperature of about 110 °C.

[0050] The term “organometallic reagent”, as used herein, relates to any organometallic reagent known to a person skilled in the art, for example, sodium acetylide 18-crown-6- complexes, acetylenic Grignard reagents, R-substituted lithium acetylide, lithium acetylide, or lithium trimethylsilylacetylide can be used as an organometallic reagent. The term “acidic catalyst”, as used herein, relates to any acidic catalyst known to a person skilled in the art, for example acidic AI ₂ O ₃ , pyridinium p-toluenesulfonate with trimethyl orthoformate, p- toluenesulfonic acid and camphorsulfonic acid.

[0051] Transparent displays typically have a shortcoming of low contrast when information is displayed, especially if the light in the surrounding is too bright. Thus, an aim of the disclosure is providing means for increasing the contrast of devices such as a transparent display. In particular, an aim of the disclosure is providing means for increasing the contrast of displays such as transparent displays under conditions of high brightness. Furthermore, the present disclosure aims at increasing the contrast of a transparent device such as a transparent display and/or projection screen, but to maintain the transparency. The present disclosure provides advantageous photochromic materials which can be embedded in thin films to provide such devices. For example, a photochromic material can be embedded in a film using an appropriate matrix, and optionally a device can comprise such film.

[0052] The present disclosure aims to provide means for products such as devices in the space projection field, which allow to produce a high quality image. The present disclosure provides photochromic materials and films, such as thin films, formed thereof in suitable matrices for use in dimming technology for transparent displays.

[0053] Advantages of the disclosure are that photochromic dyes have a fast coloring and fading time and that the photochromic dyes can be embedded in a transparent, mechanically stable, flexible, and/or adherent matrix that maintains and/or even enhances the coloring and fading time of the dye, for example a PDMS matrix. In one embodiment, the terms “photochromic molecule”, “dye” or “photochromic dye” are used to refer to a molecule according to the present disclosure. In one embodiment, the molecule according to the present disclosure is a photochromic molecule.

[0054] A preferred dye of the present disclosure has at least one of the following advantageous features: a) a rapid switching cycle (both coloration and fading) faster than 100 ms, b) intense colour development (10% transmission) upon excitation with about 350 - 420 nm (preferably with 380 - 420 nm), such as 365 nm irradiation c) colourless to black / neutral shade d) good operational lifetime (more than 100.000 times) e) single molecule preferred (mixture is acceptable) f) solubility / compatibility with polymeric host g) simple cost effective synthesis. [0055] In one embodiment, the term “alkyl” refers to a monovalent straight or branched chain, saturated aliphatic hydrocarbon radical having a number of carbon atoms in the specified range. Thus, for example, “C ₁ -C ₆ alkyl” refers to any of the hexyl alkyl and pentyl alkyl isomers as well as n-, iso-, sec-, and t-butyl, n- and isopropyl, ethyl and methyl. Alkyl groups may be optionally substituted with one or more substituents with one or more substituents as defined herein. Alkyl groups may be straight or branched. Representative branched alkyl groups have one, two, or three branches. In one embodiment, “alkyl” refers to C ₁ , C ₂ , C ₃ , C ₄ , C ₅ , C ₆ , C ₇ , C ₈ , C ₉ , C ₁₀ , C ₁₁ , C ₁₂ , C ₁ 3, C ₁₄ , C ₁₅ , C ₁₆ C ₁₇ , C ₁₈ , C ₁₉ , C ₂₀ , C ₂₁ , C ₂₂ , C ₂₃ and/or C ₂₄ , alkyl, and combinations of any of the foregoing including the ranges Ci to C ₄ , alkyl, C ₂ - C ₄ alkyl, C ₂ - C12 alkyl, C ₃ - C ₆ alkyl, C ₃ - C12 alkyl, C ₄ - C ₆ alkyl, C ₄ - C ₈ alkyl, C ₄ - Cio alkyl, C ₄ - C12 alkyl, C ₅ - C ₈ alkyl, C ₅ - C ₁₀ alkyl, C ₅ - C12 alkyl, C ₅ - Ci ₄ alkyl, C ₆ - C ₈ alkyl, C ₆ - Cio alkyl, C ₆ - C12 alkyl.

[0056] The term “alkoxy” means a group having the formula -O-alkyl, in which an alkyl group, as defined above, is attached to the parent molecule via an oxygen atom. The alkyl portion of an alkoxy group can have 1 to 20 carbon atoms (i.e., C1-C20 alkoxy), 1 to 12 carbon atoms (i.e., C ₁ -C ₁₂ alkoxy), or 1 to 6 carbon atoms (i.e., C 1-C ₆ alkoxy). Examples of suitable alkoxy groups include, but are not limited to, methoxy (-O-CH ₃ or OMe), ethoxy (- OCH ₂ CH ₃ or -OEt), t-butoxy (-O-C(CH ₃ ) ₃ or -OtBu) and the like.

[0057] The term “cycloalkyl”, alone or in combination with any other term, refers to a group, such as optionally substituted or non- substituted cyclic hydrocarbon, having from three to eight carbon atoms, unless otherwise defined. Thus, for example, “C ₃ -C ₈ cycloalkyl” refers to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Cycloalkyl groups may be optionally substituted with one or more substituents as defined herein. Cycloalkyl includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl. Examples of substituents that are suitable include but are not limited to hydroxyl, halogen, aryl(s), C ₁ - C ₅ alkyl, C ₁ , - C ₄ alkoxy, heteroaryl, heterocycloalkyl.

[0058] The term “haloalkyl” refers to an alkyl group, as defined herein that is substituted with at least one halogen. Examples of straight or branched chained “haloalkyl” groups useful in the present disclosure include, but are not limited to, methyl, ethyl, propyl, isopropyl, n- butyl, andt,-butyl substituted independently with one or more halogens, e.g. 2, 3, 4, 5 or 6 substituent halogens. The term “haloalkyl” should be interpreted to include such substituents such as -CH ₂ F, -CHF ₂ , -CF ₃ , -CH2-CH2-F, -CHF-CH2F, -CH2-CF3, and the like.

[0059] The term “halogen” refers to fluorine, chlorine, bromine, or iodine. [0060] The term “aryl” refers to any aryl group, such as (i) optionally substituted phenyl, (ii) optionally substituted benzyl, (iii) optionally substituted 9- or 10 membered bicyclic, fused carbocyclic ring systems in which at least one ring is aromatic, and (iv) optionally substituted 11- to 14-membered tricyclic, fused carbocyclic ring systems in which at least one ring is aromatic. Suitable aryls include, for example, phenyl, biphenyl, naphthyl, tetrahydronaphthyl (tetralinyl), indenyl, anthracenyl, and fluorenyl. Aryl groups may be optionally substituted with one or more substituents as defined herein. Examples of substituents that are suitable include but are not limited to hydroxyl, halogen, aryl(s), C1 - C5 alkyl, Ci - C4 alkoxy, C3 - C6 cycloalkyl, heteroaryl, heterocycloalkyl. The term “benzyl” as used herein is meant to indicate an optionally substituted or non- substituted benzyl group.

[0061] The term “heteroaryl” refers to (i) optionally substituted 5- and 6-membered heteroaromatic rings and (ii) optionally substituted 9- and 10-membered bicyclic, fused ring systems in which at least one ring is aromatic, wherein the hetero aromatic ring or the bicyclic, fused ring system contains from 1 to 4 heteroatoms independently selected from N, O, and S, where each N is optionally in the form of an oxide and each S in a ring which is not aromatic is optionally S(O) or S(O)2. Suitable 5- and 6-membered heteroaromatic rings include, for example, pyridyl, pyrrolyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, thienyl, furanyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isooxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, and thiadiazolyl. Suitable 9-and 10-membered heterobicyclic, fused ring systems include, for example, benzofuiranyl, indolyl, indazolyl, naphthyridinyl, isobenzofuiranyl, benzopiperidinyl, benzisoxazolyl, benzoxazolyl, chromenyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, isoindolyl, benzodioxo lyl, benzofuiranyl, imidazo[l,2-a]pyridinyl, benzotriazolyl, dihydroindolyl, dihydroisoindolyl, indazolyl, indolinyl, isoindolinyl, quinoxalinyl, quinazolinyl, 2,3-dihydrobenzofuiranyl, and 2,3-dihydrobenzo-l,4-dioxinyl.

[0062] The term “heterocyclyl” refers to (i) optionally substituted 4- to 8 -membered, saturated and unsaturated but non-aromatic monocyclic rings containing at least one carbon atom and from 1 to 4 heteroatoms, (ii) optionally substituted bicyclic ring systems containing from 1 to 6 heteroatoms, and (iii) optionally substituted tricyclic ring systems, wherein each ring in (ii) or (iii) is independent of fused to, or bridged with the other ring or rings and each ring is saturated or unsaturated but nonaromatic, and wherein each heteroatom in (i), (ii), and (iii) is independently selected from N, O, and S, wherein each N is optionally in the form of an oxide and each S is optionally oxidized to S(O) or S(O)2. Suitable 4- to 8-membered saturated heterocyclyls include, for example, azetidinyl, piperidinyl, morpholinyl, thiomorpholinyl, thiazolidinyl, isothiazolidinyl, oxazolidinyl, isoxazolidinyl, pyrrolidinyl, imidazolidinyl, piperazinyl, tetrahydrofiuranyl, tetrahydrothienyl, pyrazolidinyl, hexahydropyrimidinyl, thiazinanyl, thiazepanyl, azepanyl, diazepanyl, tetrahydropyranyl, tetrahydrothiopyranyl, dioxanyl, and azacyclooctyl. Suitable unsaturated heterocyclic rings include those corresponding to the saturated heterocyclic rings listed in the above sentence in which a single bond is replaced with a double bond. It is understood that the specific rings and ring systems suitable for use in the present disclosure are not limited to those listed in this and the preceding paragraphs. These rings and ring systems are merely representative. [0063] The term “optionally substituted” indicates that a group, such as alkyl, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, heterocyclyl or heteroaryl, may be unsubstituted, or the group may be substituted with one or more substituents, such as substituted with one or more of halogen, C1-C1O alkyl, C1-C3haloalkyl, C33C7cycloalkyl, oxo, -OH, aryl, heteroaryl and heterocyclyl. “Substituted” in reference to a group indicates that one or more hydrogen atoms attached to a member atom within the group is replaced with a substituent selected from the group of defined or suitable substituents. It should be understood that the term “substituted” includes the implicit provision that such substitution be in accordance with the permitted valence of the substituted atom and the substituent, and that the substitution results in a stable compound. When it is stated that a group may contain one or more substituents, one or more member atom within the group may be substituted. In addition, a single member atom within the group may be substituted with more than one substituent as long as such substitution is in accordance with the permitted valence of the atom.

[0064] In one embodiment, the molecule of the present disclosure is advantageous in that it enhances contrast of a device such as a transparent display, projection screen, and/or dimming system, and furthermore provides fast switching allowing for enhanced displaying of moving pictures such as movie projections. In one embodiment, for example, if the device is a dimming system, and absorption layer, and/or a glass, the molecule of the present disclosure is advantageous in that it enhances contrast and allows for using such device outside in the sunlight. Accordingly, using a molecule of the present disclosure, the contrast of a display, preferably transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses, can be increased. In one embodiment, when referring to a “display”, such term also refers to a transparent display, a projection screen, a dimming system, an absorption layer, and/or glass, such as eyeglasses, preferably having a display member. In one embodiment, the term “display” refers to any device having a display member.

[0065] In one embodiment, the molecules according to the present disclosure are surprisingly characterized by fast switching and fading, and strong absorption. In one embodiment, a molecule of the present disclosure or a molecule selected from TPC-0024, TPC-0033, TPC- 0054, TPC-0062, TPC-0073, UTAD, Reversacol strom purple, Reversacol plum red, Reversacol sea green, Reversacol solar yellow, RE LS-43, RE CAM 2-110, RE SA 2-51, RE SA 2-162 can be embedded in a polymeric matrix. According to the present disclosure, a film, preferably transparent film, is provided in which the molecules advantageously behave similarly as in solution, namely showing fast switching and fading, and strong absorption. [0066] In one embodiment, the molecules of the present disclosure are advantageous in that they can be embedded into a matrix, for example to provide a film, and such molecules show advantageous behavior even when embedded in a matrix, such as fast color switching and fading, and strong absorption. In one embodiment, a molecule and/or a film according to the present disclosure allow to provide transparent screen displays with high background integration and floating feeling. In one embodiment, the molecule and/or film according to the present disclosure are means for enhancing dimming on displays such as transparent screens, and such molecule and/or film can be implemented for image contrast quality improvement. In one embodiment, a black expressing beam regeneration display, preferably comprising a molecule according to the disclosure, further enhances image quality which is called “dimming” or “screen dimming”. For example, a matrix with photochromic material, preferably the molecule and/or film of the disclosure, is targeted for such screen dimming. In one embodiment, a transparent matrix that does not slow down switching time of isolated photochromic dye (diluted solution) in coloring and fading is to be used.

[0067] In one embodiment, a matrix is any of (block) copolymer bases, such as TPUs, SEBS, PMMA-PnBA, PIMs bases, such as PTMSP, inorganic-organic hybrid bases, such as SiCE-ethylenoxy hybrid, TEOS-GPTMS, Acier HC, polyurethane materials, e.g. Elastollan®, and PDMS, more preferably Elastollan® and PDMS. In one embodiment, a block copolymer is used which is composed of a high glass transition temperature (Tg) block segment and a low Tg block segment as a host matrix for the fast photochromic molecules, wherein the high Tg block segment and the low Tg segment ensure mechanical strength for industrial processing, and sufficient free and elastic volume around the photochromic molecule, respectively. In one embodiment, molecules embedded in PDMS have an even faster switching and fading behavior in matrix than in solution. In one embodiment, a matrix can be supplied with GPTMS to enhance absorption, coloring depth, and dye coloring response times.

[0068] In one embodiment, the molecule of the present disclosure is embedded in a matrix that ensures sufficient free-volume around the photochromic molecule for free rotation and that ensures the mechanical strength for industrial processing. In a preferred embodiment, the matrix is Elastollan® or polydimetylsiloxane (PDMS) which provide a highly fast switching and fading behavior of the dye, particularly even a faster switching and fading behavior of the dye in the matrix than in solution. For example, if TCP24 dye is used as molecule, PDMS is a preferred matrix, and/or if RES-06 and/or RES-042 is used as molecule, Elastollan® is a preferred matrix.

[0069] In one embodiment, a molecule of the disclosure comprises a photochromic system comprising a pyran ring fused to either a naphthalene unit to provide an isomeric 3H- naphtho[2,l-b]pyran or a 2H-naphtho[l,2-b]pyran, or fused to a benzo[c]fluorene unit to provide an indenonaphthopyran (3,13 -dihydrobenzo [h]indeno [2, l-f] chromene) or fused to a phenanthrene unit to provide a phenanthropyran (2H-dibenzo[f,h] chromene). In one embodiment, such units are optionally substituted.

[0070] In one embodiment, a molecule of the disclosure has one or more substituent(s) such as

(i) a geminal aryl unit in which either one or both of the aryl groups is/are substituted, preferably in the para-position with a strong electron donating group. Particularly, electron donating groups promote fast thermal fading of the isomeric photomerocyanines coupled with bathochromically shifted hues;

(ii) additional electron donating substituent(s) judiciously placed on the (fused) naphthalene moiety so as to either enhance the rate of fading of the photomerocyanine, e.g. a MeO substituent, and/or to increase the intensity of the chromophore, e.g. NMe2 or a morpholine unit; in one embodiment, such a substitution additionally leads to attractive neutral (dark) hues;

(iii)sterically demanding group(s), e.g. phenyl or ester; in one embodiment, such a substitution enhances the rate of ring closure of the photomerocyanine through minimizing photomerocyanine isomer formation;

(iv)aryl group(s) and hetaryl group(s); in one embodiment, such a substitution extends the conjugated system of the photomerocyanine leading to more intense absorption and a broader color gamut. [0071] In one embodiment, the method for synthesis of a molecule according to the present disclosure comprises the following step(s): i) providing a benzophenone , ii) synthesis of a 3-substituted propynol, iii) synthesis of a pyran.

[0072] In one embodiment, when referring to a “film” or a “thin film”, such film has a thickness in the range of from 100 nm to 10 mm, preferably 10 pm to 1 mm. In one embodiment, the film and/or device of the present disclosure are preferably provided at a temperature in the range of from -20 to 70°C, preferably at a temperature in the range of from 10° to 30°C.

[0073] In one embodiment, a device, such as a display, a projection screen, a dimming system, an absorption layer, and/or glass comprise(s) a display member having transmittance or reflectance that varies in accordance with first light to be applied. In one embodiment, such display member comprises the molecule according to the present disclosure. In one embodiment, the first light comprises light of a wavelength different from a wavelength of light for an image, such as the first light comprising light of a wavelength ranging from 350 nm to 420 nm or a wavelength ranging from 700 nm to 2.5 pm. In one embodiment, the display member comprises a display layer and a light-controlling layer, the display layer displaying an image, the light-controlling layer having the transmittance and the reflectance that vary in accordance with the first light. In one embodiment, a light-controlling layer comprises a photochromic material, preferably a molecule according to the present disclosure. In one embodiment, the film according to the present disclosure is a lightcontrolling layer. In one embodiment, the display layer is configured by any one of a hologram, a half mirror, a surface plasmon particle, a cholesteric liquid crystal, and a Fresnel lens. In one embodiment, the light-controlling layer has transmittance and reflectance that vary in multiple steps. In one embodiment, a protective layer is provided between the display layer and the light-controlling layer, the protective layer absorbing or reflecting the first light. In one embodiment, the display member has light-transmissivity to a wavelength in a visible region, when directly viewed.

[0074] In one embodiment, the device according to the present disclosure is a projection display apparatus, e.g. consisting of or comprising a projection screen, comprising: a light source device; an image-generating optical system that generates image light by modulating light from the light source device on a basis of an inputted image signal; a projection optical system that projects the image light generated by the image-generating optical system; and a projection screen that displays the image light projected from the projection optical system, the projection screen comprising a display member having transmittance or reflectance that varies in accordance with first light to be applied, the projection screen comprising a molecule and/or film according to the present disclosure. [0075] In one embodiment, the device of the present disclosure, e.g. the projection screen of the present disclosure, is provided with a light-controlling layer having transmittance or reflectance that varies upon application of light-controlled light. This makes it possible to enhance the contrast of the image displayed on the device, e.g. projection screen, by varying the transmittance or the reflectance of the desired region, and to improve the visibility. In one embodiment, for example in a case where the device is configured as a transparent display or projection screen, it is possible to change the desired region (black display part, for example) to black, for example, and thus to make the black luminance on the transparent display or projection screen lower than the background luminance. This makes it possible to display the image without the background being seen through, even on a transparent screen, such as a transparent display or projection screen, and thus to improve the visibility. Therefore, superior display quality becomes possible.

[0076] In one embodiment, the “display”, “transparent display”, “projection screen”, or “display member” can be implemented using any desired technology such using one or more of a LCD display, LED display, organic-LED display, a cathode ray tube, electronic paper display, transparent cylindrical display, electroluminescent (ELD) display, electrophoretic display, plasma display, Quantum dot (QLED) display, AMOLED display, swept-volume display, varifocal mirror display, emissive volume display, laser display, holographic display, static-volume display, a black expressing beam regeneration display, light field displays. In one embodiment, a display is a display for virtual reality, preferably object virtual reality. In one embodiment, the device of the present disclosure comprises or consists of any display allowing for virtual reality projections.

[0077] Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, define, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public. EXAMPLES

[0078] Example 1: Design and Synthesis of Rapid Switching Photochromic Molecules

The target outcome of the synthetic chemistry study was to synthesise a series of rapid switching photochromic molecules which met the following desired application parameters. The desired features include:

• Rapid switching cycle (both coloration and fading) within ca. 100 ms

• Intense color development upon excitation with ca. 365 nm irradiation

• Ideally colorless to black / neutral shade

• Good operational lifetime

• Single molecule preferred

• Solubility / compatibility with polymeric host

• Simple cost-effective synthesis

Photochromic systems comprising of a pyran ring fused to either a naphthalene unit to afford the isomeric 3H-naphtho[2,l-b]pyran 1 or a 2H-naphtho[l,2-b]pyran 2, or fused to a benzo[c]fluorene unit to afford an indenonaphthopyran (3,13-dihydrobenzo[h]indeno[2,l- f] chromene) 3 or fused to a phenanthrene unit leading to a phenanthropyran (2H- dibenzo[f,h] chromene) 4 were suggested, as shown below. The phenanthropyran system 4 possessed structural attributes, such as the proximity of 5-H which exert steric pressure upon the photomerocyanine favoring a rapid ring closure.

The following substituents were prominent in the structures:

(i) a geminal aryl unit in which either one or both of the aryl groups were substituted in the para-position with a strong electron donating group since such a unit promotes fast thermal fading of the isomeric photomerocyanines coupled with bathochromically shifted hues;

(ii) additional electron donating substituent(s) placed on the (fused)naphthalene moiety so as to either enhance the rate of fade of the photomerocyanine e.g. MeO substituents, or increase the intensity of the chromophore e.g. NMe2 or morpholine units;

(iii)sterically demanding groups e.g. phenyl or ester, located in appropriate sites which could enhance the rate of ring closure of the photomerocyanine through minimising photomerocyanine isomer formation; and

(iv)aryl groups and hetaryl groups which could extend the conjugated system of the photomerocyanine potentially leading to more intense absorption and a broader color gamut. Exemplary structures are presented below:

Target compounds which are derived from 2-naphthols:

Further target compounds which are derived from 2-naphthols:

[0084] 1.2 Synthesis of Propynols

[0085] With the series of amino substituted benzophenones 1 - 5, as shown hereafter, to hand their conversion to the propynols was next explored. Whilst there are options available for the preparation of propynols from benzophenones such as the use of sodium acetylide 18- crown-6-complexes or acetylenic Grignard reagents or lithium acetylide, by far the most efficient, clean and practical approach is to simply add the benzophenone to a freshly prepared anhydrous THF solution of lithium trimethylsilylacetylide, from n-BuLi and TMS- acetylene with the incorporation of either an in situ fluoride- or base- mediated silyl group removal. Using the foregoing approach, propynol 6 was prepared in an excellent 92 % yield (Scheme 3). Here it should be noted that the addition of the acetylide ion, which is normally rapid (2 - 3 h) to simple benzophenones, required nearly two days at rt to go to completion for the addition to the highly electron rich benzophenone 1 as shown hereafter.

[0089] 3-Phenyl substituted propynols were prepared by a related protocol involving the addition of phenylacetylide ion to the benzophenone precursor, however a simple aqueous work up was all that was required to isolate the target compounds 11 (51 %) and 12 (54 %) (Scheme 4). Here the difference in reaction time was again noted with the addition of phenylacetylide to benzophenone 1, as shown hereafter, taking much longer than the addition to 4,4'-difluorobenzophenone.

[0091] 1.3 Synthesis of Naphthols

[0092] Whilst 2-naphthol, 6-methoxy-2-naphthol, 4-chloro-l -naphthol, 4-methoxy-l- naphthol, 9-phenanthrol and 2,7-dihydroxynaphthalene are commercially available, the following naphthol intermediates (Figure 9) required synthesis from commercial starting materials. Here it should be noted that post-naphthopyran functionalisation is also an option at this point such that a halo-substituted naphthopyran could be obtained and a subsequent transformation, e.g. a Suzuki-Miyaura coupling reaction, could be used to introduce the final functionality.

[0094] Examination of the literature revealed that the preparation of 8-halo naphthols 13a, b had been explored by traditional diazotization and Sandmeyer type halogenation of the intermediate diazonium salt although the yields were variable. Thus, treating commercially available 8-amino-2-naphthol 14 with a cold, freshly prepared, aqueous solution of nitrous acid (NaNO ₂ , aq. HC1) followed by addition of CuBr failed to effect the clean conversion to 13a and even after extensive chromatography pure 13a could not be isolated (Scheme 5). Greater success attended the Sandmeyer type reaction of 14 with aqueous KI as the halogenating agent affording the iodonaphthol 13b, in 73 % yield (Scheme 5). The crude iodonaphthol 13b was taken on to the naphthopyran (section 2.4).

[0095] Diazotisation chemistry was also explored to obtain the 5-bromo-2-naphthol 15. In this example protection of the relatively unhindered 1 -position of the commercially available 5-amino-2-naphthol 16 by sulfonation to afford intermediate 17 was essential since the possibility of self-diazo coupling to afford colourants of the type 18 or higher oligomers, was likely during the diazotization step (Scheme 6).

[0097] Thus warming 16 in cone. H2SO4 gave after ca. 20 min a dark solid mass, presumed to be the insoluble inner salt 17, which was isolated by washing with water and then acetone. The salt 17 was then diazotised, with the intermediate diazonium salt collected by filtration and washed with ice-cold water to remove excess nitrous acid. The damp diazonium salt was transferred to a mixture of HBr, CuBr and CuBr2 Upon completion of the Sandmeyer step the crude product was isolated as the sodium sulfonate salt by ‘salting-out’. Making use of the reversibility of aromatic sulfonation the 1 -sulfonic acid sodium slat function was removed by heating in aq. H2SO4 to afford the 5-bromo-2-naphthol 15 (72 % overall).

[0098]

[0099] Furthermore, target substituted 1 -naphthols were synthesized. A short sequence developed for the construction of useful 3-substituted 1-naphthols and which has evolved as the strategy of choice to access indeno-fused napthols was next examined. Treating either 4- methoxy- or 4-dimethylamino- benzaldehyde with diethyl succinate in the presence of anhydrous NaOEt provided the crude Stobbe ‘half-acid’ condensates 19 and 20 as mixtures of geometrical isomers. Heating the foregoing ‘half-acids’ in acetic anhydride containing anhydrous NaOAc effected cyclisation to the intermediate acetates in typically moderate yield (ca. 50 %) via a purported sequence which involves mixed anhydride formation and intramolecular electrophilic trapping of the derived ketene intermediate. Acid-catalysed double trans-esterification of the acetates by heating in n-butanol containing a catalytic amount of cone. H2SO4 gave the butyl 4-hydroxynaphthalene-2-carboxylates 21 and 22 in 37 % and 42 % overall yield respectively (Scheme 7)

[00102] Application of a similar strategy (Scheme 7) to benzophenone gave the butyl 1- phenyl-4-hydroxynaphthalene-2-carboxylate 23 in comparable yield to 21 / 22 though it should be noted that the Stobbe reaction time was considerably longer (Scheme 8). With 23 to hand the intention is to convert this by addition of excess MeLi to the tertiary alcohol 24 which can then be cyclised to the 7,7-dimethyl-7Η7-benzo[c]fluoren-5-ol 25 by a Friedel- Crafts acylation involving heating with an acid-catalyst. simple filtration. Of the remaining catalyst systems, the use of the pyridinium p- toluenesulfonate (PPTS) with the trimethyl orthoformate dehydrating agent is also useful especially with substrates that either have poor solubility in toluene or possess multiple electron withdrawing groups which hinder the essential cation formation.

[00105] The following serves to demonstrate the homogeneous catalysis protocol [PPTS, (MeO)3CH)] for the preparation of a naphthopyran. Thus heating 2-naphthol, an equimolar amount of propynol 7 with 2 eq. of (MeCThCH and 0.05 eq. PPTS in 1,2-dichloroethane under reflux gave after aqueous work up and elution from silica with 10 % EtOAc in hexane the target naphthopyran (RES001) in 23 % yield (Scheme 9). Evidence for the formation of the pyran unit was obtained by ¹ H NMR spectroscopy which revealed a doublet at δ 6.2 with J = 10 Hz, typical for 2-H and the equivalent NCH2 units afforded a multiplet at δ 3.1. The pyran ring 3-C atom was clearly evident in the ¹³ C NMR spectrum and is assigned to the signal at δ 82.5.

[00106] By way of illustrating a representative procedure for the use of acidic AI2O3 (heterogeneous) catalysis a vigorously solution of 2-naphthol with propynol 6 in anhydrous PhMe was warmed to ca. 40 °C whereupon the acidic catalyst was added in a single portion and the reaction mixture brought to reflux. Heating was terminated when TLC examination of the reaction mixture indicated that no propynol remained. The cooled solution was filtered to remove the catalyst and the spent catalyst was washed with EtOAc. Removal of the combined organic solvents gave a dark gum which was eluted from silica (10 % EtOAc / PhMe) to afford the title naphthopyran RES-006 (49 %) as a pale tan solid (Scheme 10).

[00107] Heating 2,7-dihydroxynaphthalene with propynol 6 (1 eq.) in the presence of acidic alumina gave a complex reaction product from which none of the expected 9- hydroxynapthopyran 26 could be isolated by column chromatography and instead only a small amount of the symmetrical bispyran RES-011 (0.4 %) could be isolated (Scheme 11).

[00108] The target 2,2-bithienyl substituted naphthopyran was constructed by modification of a preformed naphthopyran. A series of substituted aryl and biaryl substituted naphthopyrans using transition metal-mediated cross-coupling chemistry was prepared.

Heating 5-bromo-2-naphthol 15 with the 2-thienyl substituted propynol 10 with acidic AI2O3 suspended in PhMe gave the bromo-substituted naphthopyran (RES-043) in 27 % yield after elution from silica with 20% EtOAc in hexane. The foregoing bromopyran was subjected to Suzuki cross-coupling with the commercially available 2-([2,2'-bithiophen]-5-yl)-4, 4,5,5- tetramethyl-l,3,2-dioxaborolane using our previously optimized conditions [KF, Pd(PPh3)4, PhMe:EtOH 1: 1] to prevent ring contraction of the pyran moiety to afford RES-045 in 10 % yield after elution from silica and recrystallization.

[00109]

[00115] A new phenanthropyran was obtained from 9-phenanthrol in sufficient yield. Here proposed steric interactions between the phananthrene ring protons and the vinylic protons of the photomerocyanine were such that photochromism was observed at room temperature. [00116] 2.1 Equipment and Materials

[00117] Unless otherwise stated, reagents and solvents were purchased from major chemical catalogue companies and were used as supplied. ¹ H NMR (400 MHz) and ¹³ C NMR (100 MHz) spectra were recorded on a Bruker Avance DPX400 in either CDC1 ₃ or d6-DMSO unless stated otherwise. Chemical shifts are provided in parts per million (ppm) using either the residual solvent peak or TMS as the internal reference. Coupling constants (J) are provided in Hz. All FT-IR spectra were recorded on a Nicolet 380 FTIR spectrophotometer equipped with a diamond ATR attachment (neat sample). Flash column chromatography was performed on chromatography silica gel (either Sigma- Aldrich, 40-63 micron particle size distribution or Fluorochem Silica gel 40-63 micron particle size distribution). All final compounds were homogeneous by TLC using a range of eluent systems of differing polarity (either Merck TLC aluminium sheets silica gel 60 F254 (cat. No 105554) or Fluorochem cat. No. LC0927). High resolution mass spectra were either recorded on an Agilent 6210 1200 SL TOF spectrometer or on a Thermo (Finnigan) LTQ OrbitrapXL.   

2-Naphthol (15.6 mmol, 2.25 g), l,l-bis(4-fluorophenyl)-3-phenylprop-2-yn-l-ol (15.6 mmol, 5 g), trimethyl orthoformate (31.2 mmol, 1.66 g) and PPTS (0.27 mmol, 6.7 mg) were combined in 1,2-dichloroethane (60 mL) and heated at reflux for ca. 4 hours until starting material consumed by TLC (10 % EtOAc in hexanes) at this point the mixture appeared dark blue/green. The 1,2-dichloroethane was removed by rotary evaporation and the remaining solid dissolved in DCM (50 mL), washed thoroughly with water (3 x 100 mL), dried anhyd. (NaSOL) and filtered and the solvent removed by rotary evaporation leaving the crude product as a dark blue sticky solid. The product was purified via column chromatography (10% EtOAc in hexane) to give the pure product as a white solid which was recrystallized from hexane to give a fluffy white crystalline material (3.6 g, 46%); Vmax (neat) 2361, 2341, 1623, 1598, 1587, 1503, 1259, 1191, 1002, 960, 831, 785, 713, 596, 505; ¹ H NMR (400 MHz, CDC1 ₃ ) δH 6.09 (1H, s, pyran-H), 6.96 (4H, t, J= 8.68 Hz, Ar-H), 7.02 (1H, d, J= 6.88 Hz, Ar-H), 7.07 (1H, d, J= 8.40 Hz, Ar-H), 7.19 (1H, t, J= 6.76 Hz, Ar-H), 7.29 (1H, d, J = 8.80 Hz, Ar-H), 7.32 (4H, m, Ar-H), 7.48 (4H, m, Ar-H), 7.67 (1H, d, J= 8.12 Hz, Ar-H), 7.71 (1H, d, J= 8.80 Hz, Ar-H); ¹³ C NMR (100 MHz, CDCI3) δc 81.39, 114.88, 115.10, 116.52, 118.54, 123.37, 125.24, 126.41, 127.85, 127.96, 128.44, 128.55, 128.70, 128.84, 128.92, 129.70, 130.31, 137.61, 140.01, 140.04, 140.95, 152.21, 160.90, 163.35; HRMS found [M+H] ⁺ = 447.1545; C31H20F2O requires [M+H] ⁺ = 447.1482.

[00139] RES-032

2-Naphthol (1.71g, 11.8 mmol) and 3-phenyl-l,l-bis(4-(pyrrolidin-l-yl)phenyl)prop-2-yn-l- ol (5 g, 11.8 mmol) were combined in anhydrous toluene (100 mL) and heated to 50°C at which point acidic alumina (5 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (10% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with hot toluene, these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark blue / black solid. Purification was achieved via column chromatography (SiO ₂ , 10% EtOAc in hexane) leaving the product as a light tan coloured solid (2.8 g, 37%). Vmax (neat) 3056, 2954, 2926, 2892, 2848, 2824, 1699, 1609, 1515, 1480, 1458, 1369, 1225, 1012, 945, 802, 721, 699, 527, 462; 1H N MR (400 MHz, CDC1 ₃ ) δH 1.93(8H, m, pyrrolidine-H), 3.21 (8H, t, J= 7.15 Hz, pyrrolidine-H), 6.16 (1H, s, pyran-H), 6.44 (4H, d, J= 8.58 Hz, Ar-H), 6.96 (1H, m, Ar-H), 7.07 (1H, d, J= 8.14 Hz, Ar-H), 7.13 (1H, t, J= 7.97 Hz, Ar-H), 7.29 (1H, d (obscured) Ar- H), 7.32 (5H, m , Ar-H), 7.35 (4H, d, J= 8.85 Hz, Ar-H), 7.64 (2H, m, Ar-H). ¹³ C NMR (100 MHz, CDC13 δc 25.44, 47.52, 82.52, 110.81, 116.48, 119.04, 122.67, 124.64, 126.56, 127.23, 128.03, 128.23, 128.29, 128.43, 130.31, 130.97, 131.52, 136.09, 141.80, 147.04, 153.00 ppm; HRMS found [M+H] ⁺ = 549.2900; C39H36N2O requires [M+H] ⁺ = 549.2828.

[00140] RES-033

4-morpholino-2-naphthol (0.81 g, 3.54 mmol) and 3-phenyl-l,l-bis(4-(pyrrolidin-l- yl)phenyl)prop-2-yn-l-ol (1.5 g, 3.54 mmol) were combined in anhydrous toluene (50 mL) and heated to 50°C at which point acidic alumina (2 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (10% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with warm toluene (50 mL), these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was achieved via column chromatography (SiΟ ₂ , 10% EtOAc in hexane) leaving the product as a crystalline white coloured solid (0.81 g, 36.5%); vmax (neat) 2961, 2840, 2359, 2342, 1704, 1607, 1586, 1518, 1484, 1456, 1436, 1368, 1287, 1273, 1181, 1156, 1116, 1072, 963, 848, 807, 762, 519; ¹ H NMR (400 MHz, CDC13 δH 1.94 (8H, t, J= 6.47 Hz, pyrrolidine-H), 3.11 (4H, bs, morpholino-H), 3.21 (8H, t, J= 6.56 Hz, pyrrolidine-H), 3.95 (4H, t, J= 4.81 Hz, morpholino-H), 6.04 (1H, s, pyran-H), 6.44 (4H, d, J= 8.74 Hz, Ar-H), 6.90 (1H, s, 5-H), 6.95 (1H, t, J= 7.07 Hz, Ar-H), 7.09 (1H, d, J = 8.46 Hz, Ar-H), 7.13 (1H, t, J= 7.02 Hz, Ar-H), 7.33 (9H, m, Ar-H), 8.00 (1H, d, J= 8.23 Hz, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 25.46, 47.54, 53.38, 67.38, 82.67, 107.92, 110.81, 110.81, 112.53, 122.28, 123.58, 124.75, 125.20, 127.16, 127.31, 128.04, 128.25, 128.44, 129.30, 131.14, 131.68, 135.91, 141.92, 147.03, 151.47, 153.21 ppm; HRMS found [M+H] ⁺ = 634.3427; C43H43N3O2 requires [M+H] ⁺ = 634.3355.

4-Methoxy-l -naphthol (0.62 g, 3.54 mmol) and 3-phenyl-l,l-bis(4-(pyrrolidin-l- yl)phenyl)prop-2-yn-l-ol (1.5 g, 3.54 mmol) were combined in anhydrous toluene (50 mL) and heated to 50°C at which point acidic alumina (2 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (10 % EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with warm toluene (50 mL), these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was achieved via column chromatography (SiO ₂ , 10% EtOAc in hexane) leaving the product as a crystalline blue coloured solid (0.69g, 34%); Vmax (neat) 2969, 2358, 2341, 1704, 1606, 1485, 1455, 1271, 1212, 1157, 1072, 953, 809, 762, 699, 528; 1 H NMR (400 MHz, CDC 1 ₃ δH 1.94 (8H, m, pyrrolidine-H), 3.22 (8H, m, pyrrolidine-H), 3.74 (3H, s, OMe), 6.16 (1H, s, pyran-H), 6.47 (4H, d, J= 8.86 Hz, Ar-H), 6.51 (1H, s, Ar-H), 7.37-7.54 (11H, m, Ar-H), 8.09 (1H, d, 7.86 Hz, Ar-H), 8.38 (1H, d, J = 8.23 Hz, Ar-H). ¹³ C NMR (100 MHz, CDC 1 ₃ δc 25.48, 47.53, 55.69, 82.61, 101.87, 110.87, 116.16, 121.71, 122.47, 125.59, 125.90, 126.02, 126.20, 126.46, 126.69, 127.65, 128.15, 128.30, 128.91, 132.34, 135.76, 139.01, 142.83, 146.98, 148.77 ppm; HRMS found [M+H] ⁺ = 275.1282; CI ₆ H _I8 O ₂ requires [M+H] ⁺ = 275.1205.

[00142] RES-035

4-Chloro-l -naphthol (0.63 g, 3.54 mmol) and 3-phenyl-l,l-bis(4-(pyrrolidin-l- yl)phenyl)prop-2-yn-l-ol (1.5 g, 3.54 mmol) were combined in anhydrous toluene (50 mL) and heated to 50 °C at which point acidic alumina (2 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (10% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with hot toluene, these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was attempted via column chromatography (SiCh, 10% EtOAc in hexane) leaving a very small fraction of the product pure as a grey coloured solid (0.050 g, 3 %); ¹ H NMR (400 MHz, CDC1 ₃ δH 2.06 (8H, m, pyrrolidine-H), 3.45 (8H, m, pyrrolidine- H), 6.62 (1H, s, pyrrolidine-H), 6.75 (4H, m, Ar-H), 7.13 (4H, m, Ar-H), 7.33 (3H, m, Ar-H), 7.41 (2H, m, Ar-H), 7.43 (1H, m, Ar-H), 7.60 (1H, t, J= 7.29 Hz, Ar-H), 8.12 (1H, d, J= 7.51 Hz, Ar-H), 8.31 (1H, d, J= 7.55 Hz, Ar-H); ¹³ C NMR (100 MHz, CDC ₁₃ δc 25.50,

50.62, 90.11, 112.32, 113.44, 115.56, 123.65, 123.81, 124.12, 124.39, 125.47, 127.23,

127.86, 128.36, 128.68, 128.79, 129.20, 130.89, 134.25,135.90, 140.02, 151.20, 152.81. A solution of 4-methoxybenzaldehyde (20 g, 147 mmol) and diethyl succinate (38.4 g, 220 mmol) in anhydrous EtOH (150 mL) was added dropwise to a stirred solution ofNaOEt (from Na 6.76 g, 293 mmol) in anhydrous EtOH (150 mL) under N2. The solution was heated at reflux for 24 h cooled, reduced, poured into water (500 mL), neutralised with HC1 (2 M), extracted with EtOAc (3 x 100 mL). The combined extracts were washed with water (100 mL), dried (Na2SO4) and the solvent removed under reduced pressure. The crude mixture of 1-ethyl-4H -2-[diphenylmethylene]butandioate and anhyd. NaOAc (18.02 g, 220 mmol) in AC2O (300 mL) was heated at reflux for 3 h with stirring, cooled and poured into water (2 L). The mixture was stirred for 16 h, filtered, washed with water (500 mL) to afford the crude intermediate ethyl 4-acetoxy-6-methoxynaphthalene-2-carboxylate as a tan coloured solid. A small quantilty was recrystallized from EtOAc / hexane to give tan coloured micro-crystals, m.p. 92 - 95 °C; δH 1.42 (3H, t, J= 7.3, CH2CH3), 2.48 (3H, s, Ac), 3.94 (3H, s, OMe), 4.41 (2H, q, J= 1.3, OCH ₂ ), 7.10 (1H, d, J= 1.5, 5-H), 7.21 (1H, dd, J = 9.0, 1.5, 7-H), 7.81 (1H, d, J= 1.5, 3-H), 7.83 (1H, d, J= 9.0, 8-H), 8.44 (1H, s, 1-H). Found: MH ⁺ = 289.1074. C ₁₆ H ₁₆ O ₅ requires MH ⁺ = 289.1076.

The foregoing crude tan solid was dissolved in 1-butanol (400 mL), H2SO4 (10 mL) was added and the solution heated at reflux for 6 h, cooled, poured into water (1 L), extracted with EtOAc (2 x 500 mL), washed with water (300 mL), dried (Na2SO4) and the solvent removed under reduced pressure to leave the crude product as a brown coloured solid (14.8g, 37% overall yield); Vmax (neat) 3412, 2957, 2931, 2870, 2359, 2337, 1688, 1628, 1604, 1585, 1486, 1369, 1303, 1234, 1179, 1060, 977, 851, 813, 767564, 531; 1H NMR (400 MHz, CDC 1 ₃ δH 0.98 (3H, t, J= 1A Hz, CH ₃ ), 1.49 (2H, sext, J= 7.4 Hz, CH ₂ ), 1.78 (2H, pent, J= 6.7 Hz, CH ₂ ), 3.94 (3H, s, 6-OMe), 4.37 (2H, t, J= 6.6 Hz. OCH ₂ ), 6.30 (1H, bs, OH), 7.18 (1H, dd, J= 2.5, 9.0 Hz, 7-H), 7.54 (1H, d, J= 2.5 Hz, 5-H), 7.65 (1H, d, J= 1.4 Hz, 3-H), 7.79 (1H, d, J= 9.0 Hz, 8-H), 8.11 (1H, d, J= 1.4 Hz, 1-H). ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 13.80, 19.32, 30.83, 55.47, 65.13, 100.30, 108.27, 120.05, 123.37, 125.28, 128.29, 129.14, 130.75, 150.26, 159.26, 167.47 ppm.

[00144] RES-037

A solution of 4-(dimethylamino)benzaldehyde (20 g, 134 mmol) and diethyl succinate (35.0 g, 201 mmol) in anhydrous EtOH (150 mL) was added dropwise to a stirred solution of NaOEt (from Na 6.16 g, 268 mmol) in anhydrous EtOH (150 mL) under N2. The solution was heated at reflux for 24 h cooled, reduced, poured into water (500 mL), neutralised carefully to pH 5.5 with HC1 (2 M), extracted with EtOAc (3 x 100 mL). The combined extracts were washed with water (100 mL), dried (Na2SO4) and the solvent removed under reduced pressure. The crude mixture of l-ethyl-4H -2-[diphenylmethylene]butandioate and anhyd. NaOAc (16.5 g, 201 mmol) in AC ₂ O (300 mL) was heated at reflux for 3 h with stirring, cooled and poured into water (2 L). The mixture was stirred for 16 h, filtered, washed with water (500 mL) to afford a tan coloured solid which was dissolved in 1 -butanol (400 mL), H ₂ SO ₄ (10 mL) was added and the solution heated at reflux for 6 h, cooled, poured into water (1 L), extracted with EtOAc (2 x 500 mL), washed with water (300 mL), dried (Na ₂ SO ₄ ) and the solvent removed under reduced pressure to leave the crude product as an oily brown coloured solid (16.2g, 42 % overall yield); Vmax (neat) 2956, 2871, 2724, 1718, 1681, 1609, 1488, 1474, 1408, 1381, 1201, 1188, 1167, 1146, 1099, 1060, 974, 946, 888, 835, 810, 770, 761, 577, 550, 447; ’H NMR (400 MHz, CDC1 ₃ ) δH 0.86 (3H, t, J= 8.53 Hz, CH ₃ ), 1.39 (2H, m, CH ₂ ), 1.65 (2H, m, CH ₂ ), 3.44 (6H, s, N(CH ₃ ) ₂ ), 4.20 (2H, t, J= 6.39 Hz, OCH ₂ ), 7.46 (1H, s, Ar-H), 7.53 (1H, d, J= 8.53 Hz, Ar-H), 7.78 (1H, d, J= 9.0 Hz, Ar-H), 7.90 (1H, s, Ar-H), 8.23 (1H, s, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 13.79, 18.94, 30.79, 46.22, 68.69, 109.32, 117.59, 121.71, 126.79, 131.76, 152.87, 166.51 ppm; HRMS found [M+H] ⁺ = 288.1596; C17H21NO3 requires [M+H] ⁺ = 288.1521.

[00145] RES-038

A solution of benzophenone (20.0 g, 110 mmol) and diethyl succinate (20.0 g, 115 mmol) in anhydrous EtOH (150 mL) was added dropwise to a stirred solution of NaOEt (from Na 5.56 g, 241 mmol) in anhydrous EtOH (150 mL) under N2. The solution was heated at reflux for 24 h cooled, reduced, poured into water (500 mL), neutralised with HC1 (2 M), extracted with EtOAc (3 x 100 mL). The combined extracts were washed with water (100 mL), dried (Na2SO4) and the solvent removed under reduced pressure. The crude mixture of I -ethyl-47H- 2-[diphenylmethylene]butandioate and anhyd. NaOAc (9.43 g, 115 mmol) in AC ₂ O (300 mL) was heated at reflux for 3 h with stirring, cooled and poured into water (2 L). The mixture was stirred for 16 h, filtered, washed with water (500 mL), dissolved in 1 -butanol (400 mL), H2SO4 (10 mL) was added and the solution heated at reflux for 6 h, cooled, poured into water (1 L), extracted with EtOAc (2 x 500 mL), washed with water (300 mL), dried (Na2SO4) and the solvent removed under reduced pressure to leave the crude product as an oily brown coloured solid (12.9 g, 37% overall yield); Vmax (neat) 3376, 2980, 2359, 2341, 1682, 1621, 1596, 1518, 1495, 1470, 1440, 1377, 1351, 1247, 1232, 1154, 1115, 1075, 1029, 1012, 857, 771, 759, 700, 635, 618, 610, 561; ¹ H NMR (400 MHz, CDC1 ₃ ) δH 0.91 (3H, t, J= 8.53 Hz, CH ₃ ), 1.12 (2H, m, CH ₂ ), 4.02 (2H, m, OCH ₂ ), 7.27 (3H, m, Ar-H), 7.42 (4H, m, Ar-H), 7.54 (2H, m, Ar-H), 8.28 (1H, d, J= 8.53 Hz, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ δc 13.51, 61.04, 107.98, 121.78, 126.77, 127.02, 127.05, 127.75, 127.80, 130.17, 134.16, 139.33 ppm; HRMS found [M+H] ⁺ = 321.1481; C21H20O3 requires [M+H] ⁺ = 321.1412.

[00146] RES-039

(4-Fluorophenyl)(thiophen-2-yl)methanone (10.0 g, 48.4 mmol) and pyrrolidine (17.2 g, 242.2 mmol) were combined in a round bottom flask and heated at reflux for ca. 14 hrs with monitoring by TLC (SiO ₂ , 50 % EtOAc in hexane). On completion the cooled mixture was poured into water (500 mL) and the resulting precipitate collected by filtration and allowed to air dry. The crude solid was added to toluene (100 mL) and heated at reflux for 30 minutes, allowed to cool and filtered, the resulting product washed with Et ₂ O (3 x 50 mL) leaving the pure product as a pale orange/brown solid (10.4 g, 84 %); ¹ H NMR (400 MHz, CDC1 ₃ ) δH 2.05 (4H, m, pyrrolidine-H), 3.39 (4H, m, pyrrolidine-H), 6.57 (2H, d, J= 8.76 Hz, Ar-H), 7.14 (1H, t, J= 3.84 Hz, thiophene-H), 7.62 (2H, m, thiophene-H), 7.90 (2H, d, J= 8.81 Hz, Ar-H). This material was used directly in the subsequent step. n-BuLi (6.85 mL, 2.5 M in hexanes, 17.6 mmol) was added dropwise via syringe to a cold (-5 °C) stirred solution of TMS-acetylene (2.45 mL, 17.6 mmol) in anhydrous THF (50 mL) under N2. The solution was stirred for a further 30 minutes at -5 °C. (4-(Pyrrolidin-l- yl)phenyl)(thiophen-2-yl)methanone (5.0 g, 17.6 mmol) in anhydrous THF (30 mL) was added in a single portion, the ice bath was removed and the reaction allowed to warm to room temperature and stirred for ca. 16 hours, at this point TLC (SiO ₂ , 20 % EtOAc in hexane) indicated completion of the reaction. The solution was re-cooled to 0 °C and a solution of methanolic KOH (85 %, 8.3 g, 126 mmol / MeOH (10 mL )) was added in a single portion, TLC indicated that deprotection had occurred almost immediately. The mixture was poured into water (300 mL) and extracted with EtOAc (3 x 100 mL), the organic fractions were combined and washed thoroughly with water (6 x 100 mL), dried anhyd. (Na2SO4) and the solvent removed via rotary evaporation leaving the pure product as a beige coloured solid (15.8 g, 88 %); vmax (neat) 3297, 2979, 2835, 2360, 2341, 1607, 1510, 1457, 1378, 1352, 1316, 1229, 1173, 1142, 1062, 1031, 977, 950, 813, 749, 712, 667, 652, 601, 532, 462; ’H NMR (400 MHz, CDCh) 8H 2.12 (4H, m, pyrrolidine-H), 3.40 (4H, m, pyrrolidine-H), 3.25 (1H, vbs, OH), 3.97 (1H, s, alkyne-H), 6.75 (2H, d, J= 7.45 Hz, Ar-H), 7.14 (4H, m, Ar-H), 7.62 (1H, d, J= 7.87 Hz, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 25.49, 25.61, 47.61, 67.94, 71.74, 74.43, 86.35, 111.09, 125.28, 125.66, 126.40, 126.86, 130.43, 147.82, 150.41 ppm; HRMS found [M+H] ⁺ = 284.1103; C17H17NOS requires [M+H] ⁺ = 284.1031. n-Butyl 6-(dimethylamino)-4-hydroxy-2-naphthoate (4.15 g, 14.4 mmol) and l, l-bis(4- (pyrrolidin-l-yl)phenyl)prop-2-yn-l-ol (5.0 g, 14.4 mmol) were combined in anhydrous toluene (100 mL) and heated to 50 °C at which point acidic alumina (6 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (20% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with hot toluene, these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was achieved via column chromatography (SiO ₂ , 20% EtOAc in hexane) leaving the product as a brown coloured solid which was recrystallized from EtOAc/pentane affording the pure product as a yellow coloured solid (2.39g, 26 %); Vmax (neat) 2960, 2870, 2359, 2341, 1704, 1605, 1586, 1519, 1484, 1456, 1370, 1273, 1204, 1181, 1155, 1117, 1072, 963, 951, 889, 812, 765, 668, 515; ¹ H NMR (400 MHz, CDC1 ₃ ) δH 0.99 (3H, t, J= 7.24 Hz, CH ₃ ), 1.50 (2H, m , CH2CH3), 1.76 (2H, m, CH2CH2CH3), 1.50 (8H, m, pyrrolidine-H), 2.87 (6H, s, N(CH ₃ ) ₂ ), 3.35 (8H, m, pyrrolidine), 4.32 (2H, t, J= 5.45 Hz, COOCH2), 5.83 (1H, d, J= 10.9 Hz, pyran-H), 6.44 (4H, app. d, J= 7.62 Hz, Ar-H), 6.62 (3H, m, Ar-H), 7.09 (1H, d, J= 8.76 Hz, Ar-H), 7.17 (3H, d, J= 8.04 Hz, Ar-H), 7.39 (2H, d, J= 8.48 Hz, Ar-H), 7.65 (1H, d, J= 8.72 Hz, Ar-H), 7.98 (1H, s, Ar- H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 13.82, 19.37, 25.45, 25.54, 30.90, 41.58, 47.55, 64.60, 89.03, 99.45, 110.98, 111.05, 119.52, 119.62, 119.75, 123.79, 126.09, 126.61, 129.50, 129.72, 131.71, 147.46, 167.68 ppm; HRMS found [M+H] ⁺ = 616.3541; C ₄₀ H ₄₅ N ₃ O ₃ requires [M+H] ⁺ = 616.3461. n-Butyl 4-hydroxy-6-methoxy-2-naphthoate (3.96 g, 14.4 mmol) and l, l-bis(4-(pyrrolidin-l- yl)phenyl)prop-2-yn-l-ol (5.0 g, 14.4 mmol) were combined in anhydrous toluene (100 mL) and heated to 50 °C at which point acidic alumina (6 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (20% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with hot toluene, these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was achieved via column chromatography (SiO ₂ , 20% EtOAc in hexane) and recrystallized from acetone/methanol affording the title compound as a very pale 7.35 (4H, d, J= 8.32 Hz, Ar-H), 7.62 (3H, m, Ar-H), 7.96 (1H, s, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 13.84, 19.40, 25.49, 30.86, 47.52, 55.55, 64.67, 82.76, 100.57, 110.82, 115.66, 119.45, 121.17, 122.35, 124.12, 128.01, 128.29, 129.41, 130.42, 132.06, 147.98, 159.22, 167.43 ppm.

5-Bromonaphthalen-2-ol (1.0 g, 4.48 mmol) and l-(4-(pyrrolidin-l-yl)phenyl)-l-(thiophen-2- yl)prop-2-yn-l-ol (1.27 g, 4.48 mmol) were combined in anhydrous toluene (50 mL) and heated to 50 °C at which point acidic alumina (6 g) was added in a single portion and the reaction heated at reflux until complete consumption of the alkynol by TLC (20% EtOAc in hexane) ca. 5 hrs. Upon completion the cooled mixture was filtered to remove the remaining alumina and the solid waste washed with hot toluene, these washings were combined with the filtrate and the solvent removed by rotary evaporation leaving the crude product as a dark brown solid. Purification was achieved via column chromatography (SiO ₂ , 20% EtOAc in hexane) leaving the title compound as a grey/brown coloured solid (0.6g, 27%); ¹ H NMR (400 MHz, CDC1 ₃ ) δH 1.95 (4H, m, pyrrolidine-H), 3.24 (4H, m, pyrrolidine-H), 6.28 (1H, d, J= 9.8 Hz, pyran-H), 6.49 (2H, app. d, J= 7.71 Hz, Ar-H), 6.92 (2H, m, Ar-H), 7.23 (4H, m, Ar-H), 7.38 (2H, d, J= 7.71 Hz, Ar-H), 7.59 (1H, d, J= 7.16 Hz, Ar-H), 7.91 (1H, d, J= 7.71 Hz, Ar-H), 8.07 (1H, d, J= 8.82 Hz, Ar-H); ¹³ C NMR (100 MHz, CDC1 ₃ ) δc 25.49, 47.53, 80.79, 110.92, 114.11, 118.88, 119.74, 121.31, 123.59, 125.99, 126.03, 126.34, 126.78, 127.64, 127.71, 128.58, 128.94, 130.43, 131.16, 147.52, 150.01, 151.12 ppm.

[00151] RES-045

mixture of PhMe and EtOH (20 mL) was heated at reflux under N2 for 48 Hrs. After this time the mixture was evaporated to dryness and the resulting residue dissolved in DCM (50 mL), washed with water (3 x 50 mL), dried with anhydrous sodium sulfate and the solvent removed by rotary evaporation leaving the crude product as a dark purple solid. Purification was achieved via column chromatography (SiCL, 20% EtOAc in hexane) and recrystallization (EtOAc/pentane) leaving the title compound as a light brown solid (0.09 g, 10.2 %); ’H NMR (400 MHz, CDC1 ₃₎ δH 1.96 (4H, m, pyrrolidine-H), 3.25 (4H, m, pyrrolidine-H), 6.18 (1H, d, J= 10.34 Hz, pyran-H), 6.50 (2H, app. d, J= 8.27 Hz, Ar-H), 6.93 (2H, app. d, J= 10.73 Hz, Ar-H), 7.05 (2H, m, Ar-H), 7.22 (7H, m, Ar-H), 7.38 (2H, d, J= 7.72 Hz, Ar-H), 7.60 (1H, d, J= 6.72 Hz, Ar-H), 7.93 (1H, d, J= 7.92 Hz, Ar-H), 8.08 (1H, d, J= 8.64 Hz, Ar-H); ¹³ C NMR (100 MHz, CD1 ₃ ) δc 25.48, 47.52, 110.90, 114.09, 118.87, 119.74, 121.30, 123.58, 123.76, 124.25, 124.39, 124.58, 125.97, 126.01, 126.33, 126.77, 127.63, 127.70, 127.75, 127.92, 128.56, 128.94, 131.15, 147.51, 149.99, 151.11 ppm.

[00152] Example 2: Response time set up

[00153] In order to be able to make precise measurements, a set-up for the measurement of the coloring and fading response times of UV-light switchable photochromic dyes was built. The set-up was designed “vertically” so that the sample could placed at the measurement position without the need of a clamp. The white light source was mounted below the main plate of the set-up with the light going up and passing a metal mask with a drilled hole of 1.5 mm ² diameter. The UV-lamp was fixed on a tilted plane next to the sample with a precise angle of 30°. The extended central axis of the UV-lamp runs through point of measurement where the white light hits the sample. A UV-sensor (Panasonic UJ35 UV sensor) was mounted on a teflon block on a tilted plane with an angle of 60°, which could be slid to the left so that the senor was placed precisely at the point of measurement, enabling a UV- intensity measurement at a vertical angle of incidence exactly at the measurement position. After passing through the sample, the white light was collected by a collimator which was coupled to a glass fiber connected to the spectrometer. In a second version, the sample was placed inside a Linkam temperature stage for measurements at varied temperatures (both heating and cooling). The coloring and fading response times were determined by 90% thresholds as shown in Figure 3.

[00154] Example 3: Characterization of dye in solution

[00155] The first evaluation of the response time of the photochromic dyes was done in solution. The developed dyes were characterized in addition to commercial dyes. Particularly, the following dyes were analyzed: commercial dyes TPC-0024, TPC-0033, TPC-0054, TPC-0062, TPC-0072, 2NpNP, UTAD, and newly developed dyes RES-004, RES-006, RES-007, RES-010, RES-015, RES-022, RE SA 2-51, RE CAM 2-110, RES-31, RES-33, RES 35, RES 045, Reversacol Seagreen, Reversacol Solaryellow, Reversacol Stormpurple, Reversacol Plumred, RES-011, RE SA 2-162, RE LS-43, RES-23, RES-32, RES-34, RES 41, RES 42.

[00156] Photographs of the solutions made in toluene with a concentration of 10- ³ - 1 O- ⁴ mol/1 were taken. The solutions were illuminated with a UV pen having a wavelength of 385 nm to observe the response of the dye. Furthermore, UV/vis characterization was performed by dissolving the dyes in toluene in a 1 cm width Quartz glass cuvette (3 ml volume). In almost all cases the solution were transparent (except for RES-023), the dyes absorbed only in the UV region.

[00157] Visible light spectra were recorded in the response time measurement setup during excitation by UV. The solution of ~10- ³ mol/1 was filled into glass cells KSSZ- 30/B511P7NSS (EHC Japan) with 30 pm gap size to achieve a defined path length in solution. All dyes were absorbing in the visible range showing coloring going from yellow to dark violet/brown (cf. Figure 4).

[00158] All dyes were systematically characterized. RES-006 was the fastest dye of the developed dyes, especially with regard to fading, while the RES-042 showed the strongest absorption. The overview of the measurement results is shown in Figure 5. All developed dyes were measured at 24°C, after UV light irradiation (max. at 365 nm; 0.5 W/cm ² ) and with 5 ms integration time. The initial characterization of the commercially available materials as well as the UTAD dyes (first table) was done using 1.4 W/cm ² UV intensity. Coloring response is proportional to 1/UV intensity. Therefore, values at 0.5W/cm ² should be approximately 3 times higher.

[00159] Example 4: Matrix investigation and exemplary matrix materials

[00160] The photochromic material is preferably embedded in a support in order to be used in a product such as an OVR screen.

[00161] The softness of the matrix material is an important factor, which is proven by a strong hysteresis phenomena as well as long coloring response times in rigid matrices, such as Hard Coat or PTMSP. With their glass transition temperature (Tg) around -34°C or lower, TPU materials and PDMS show some of the best switching performances by contrast.

[00162] The coloring intensity and minimum transmission during UV irradiation are best in either strongly concentrated or rather thick -100 pm films. High film thicknesses are preferably achieved using coating methods such as drop casting, doctor blading or spin coating using viscous solutions.

[00163] Several matrix polymers were studied, such as tri-block acrylic-based polymer comprising poly(methyl methacrylate) (PMMA) and poly(-butyl acrylate) (PBA), as well as Styrenic Block Copolymer (SEBS). Low T _g of the matrix has a positive effect on the photochrome (PC) switching. Higher molecular weight (M _w ) leads to higher viscosities, which makes it preferable to use a polymer with low polymer chain length (M _w < 100 000). Furthermore, using a thermoplastic polyurethane (TPU) as in the impregnation method has numerous advantages. The TPU structure allows for processing via dissolution or melting and is a stable material which comprises soft phases for photochromic dye switching. Particularly, the glassy state of the hard segments is combined with the rubbery state of the soft segments in a single material.

[00164] TPU materials

The present inventors have adapted an impregnation method, which involves photochromic dye uptake by TPU rubber film swelling in organic solvent followed by drying. Using the methodology for impregnation, homogeneous films with high absorption were obtained. The microscopic and optical appearance of the cast TPU films were even improved by casting onto a flat native oxide Si wafer surface. Possibly occuring haziness when cast on glass is caused by small bubbles on the TPU facing the glass petri dish, and such bubbles do not form on Si wafer. Photos and microscope images of the improvement are shown in Figure 7. The impact of different dipping times on PC response was low, thus 15 min is considered long enough for the impregnation step (cf. Figure 8). TPU Elastollan® was also used and compared to Resamin. The present inventors optionally softened the TPU Elastollan® matrix by addition of GPTMS. The addition of 10 wt% GPTMS led to an improvement in the PC response of the TPU films, namely

• stronger absorption/coloring depth

• faster response time in case of TPC24 and TPC33; slower in case of UTAD

• slower fading time in all cases.

[00165] SiO ₂ , sol gel

By the sol-gel method, the present inventors wanted to insert elastomers in the SiCE sol-gel (based on TEOS monomers) to introduce free mobility for PC dye switching (cf. Figure 9). The solutions were clear and colorless after preparation, and showed photochromic responses when irradiated with 365nm UV. The solutions were used for film formation on different surfaces, such as glass, Teflon, Zeonex, and PMMA.

The response of dye for both TEOS:GPTMS solutions were stronger than the TEOS solution. THF -based PC solutions mixed in with the sol were prepared to enhance solubility. Photochromic behavior was measured with following outcome:

• The higher amount of GPTMS (66%) in TEOS showed a slower coloring (~4x) but also a faster fading (~5x).

• The lower amount of GPTMS (10%) showed a faster fading.

• Using a three times thinner film did not show a difference in the minimal transmission. But the films were still quite thin with <2pm.

[00166] Hard Coat

Acier Hard Coat (Nidek Co., Ltd.) is a highly transparent compound material based on acrylate and amorphous silica. It is thus another type of inorganic-organic hybrid material which can be used for embedding a dye of the present disclosure (cf. Figure 10). TPC24 was used as an exemplary dye. Clear thin films were obtained by dip-coating onto COP or PMMA.

[00167] Polymers of intrinsic microporosity

The present inventors tested polymers of intrinsic microporosity (PIMs) to provide a suitable environment for photochromic switching based on the high surface area provided by the organic micropores (cf. Figure 11). PIMs are solution-processable which is a major advantage. Spincoated (2 pm at 500rpm for 60sec) and drop casted (20-30pm) films with 5% PTMSP solution were prepared on PMMA, COP and glass substrates. In one embodiment, COP has even more advantageous features than PMMA. The following results were obtained:

• using COP as substrate gives deeper transmission values compared to PMMA,

• using 1% PTMSP solution onto COP gives a similar response and fading time,

• using GPTMS with PTMSP onto COP slows down the switching,

• using a three times thicker film having a thickness <2μm did not show a difference in the transmission minimum value,

• the 20-30pm thick films onto glass show slower coloring and fading.

[00168] PDMS

PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties. Films were prepared with TCP-024 using the impregnation method and direct mixing of the dye in the polymer. Very high absorption, fast coloring and fast fading despite saturation in absorption were measured. Fastest fading was observed for PDMS impregnation.

Table 3: PDMS films.

(TCP-24) and the comparison of different matrixes was performed using the standard dye.

Figure 12 shows the observed features of the different matrices.

Fast switching is demonstrated using the various dyes and matrices, such as using TPU Resamine and a PDMS matrix. The PDMS matrix has a low glass transition temperature as well as polarity and a morphology that can facilitate the isomerisation of the close-opening reaction during the photonic-thermal equilibrium reaction.

[00169] Example 5: Dye content in matrix determination

[00170] An important characteristic of the polymer matrix used to produce photochromic solid films is the dye that is taken up by the matrix upon dipping in the dye solution and the amount of dye that stays in the matrix after drying. This amount was calculated using calibration curves in solution both in the UV and visible region and calculating the corresponding extinction coefficients ε. Exemplary results obtained for TCP33 in the UV region and visible region are shown in Figure 13.

[00171] Absorbance measured with the spectrometer is in good agreement with absorbance derived from the transmission. The absorbance values are lower than in UV due to reduced path length 1 (1 cm versus 30 pm). Applying the Beer-Lambert absorption law the extinction coefficient could be determined as ε=53100 at 545 nm as compared to ε=9720 at 362 nm. The results were applied to the TPU film containing TCP33 and are shown in Table 2.

Derived concentrations in visible are lower than those in UV possibly caused by reduced activity due to hindrance by the matrix.

[00172] Example 6: Parameters affecting photochromic performance

[00173] The present inventors performed different methodological investigations in order to see which parameters influence the response time of the system. In particular, the effect of measurement conditions such as UV pulse intensity and film temperature were studied. Moreover, the effect of sample preparation methods such as dye concentration and dye per unit area, as well as the influence of matrix, solution, and vacuum heating were investigated. The coloring response time is strongly affected by UV pulse intensity with for both solution and solid film. The fading time only weakly decreases with intensity as it can be seen in Figure 14a for TCP33 in TPU.

[00174] Regarding temperature behavior, in general, the minimum transmission increased with higher temperature, thus lowering the coloring intensity as the film gets heated. The coloring response time slightly decreases, which might be related to the changes in minimum transmission. Minimum transmission and coloring response time of TPC24 in TPU is shown in Figure 14b.

[00175] The fading time also decreases with higher temperature. The fading response times have a very strong temperature dependence which can be well fitted by an exponential decay. Polymer matrix softening at higher temperature may be the reason for these phenomena. TPU is operated significantly above its Tg of -34°C, but further softening at higher temperature is still possible. The dependence of response time and minimum transmission on dye concentration was studied as well. The minimum transmission significantly decreased as the concentration of dye in solution was increased, i.e. the coloring is more intense at higher dye concentrations.

[00176] The coloring response time was weakly decreasing against dye concentration. Fading response times were found to be approximately constant; however, the completely absorbing solution at 10- ² mol/L with the s-shaped curve showed an increase in fading time (Figure 14c). There is a trade-off between minimum transmission/coloring intensity and fading time. In one embodiment, a molecule of the disclosure is highly advantageous in that it has a short fading time and/or provides a low minimum transmission.

[00177] Multi-layers of photochromic film were prepared in order to examine how the amount of dye per unit area affects the response while keeping the concentration in solid film constant. This can be explained by the fact that e.g. two layers of the same photochromic film piece comprise twice the amount of dye per unit area as compared to a single layer.

[00178] Finally temperature dependence coloring and switching time were evaluated. UTAD dye in different matrices was evaluated (Figure 15). Different coloring responses at two different temperature regions were observed for all combinations, namely a strong decrease up to approx. 0°C and a slower curved decrease above 0°C. An initial fast decrease was not observed for PDMS.

[00179] Different coloring responses at two different temperature regions were observed for all films (Figure 15 A); a strong decrease up to approx. 10°C and a slower decrease above 10°C. The same temperature region ranges were also observed in transmission. Slightly lower fading response times were observed in the first region for PDMS in accordance to coloring behavior. The effect of the matrix on fading is masked by strong inherent temperature dependence of the dyes.

[00180] Temperature dependence of different dyes in TPU Resamine was also investigated. Varying coloring responses at three different temperature regions were observed; a rapid decrease up to approx. -10°C; then a plateau (with exception RES-34); and a slower decrease above 20°C (Figure 15B). The strongest variations between dyes were observed at higher temperatures.

[00181] Different fading responses at two different temperature regions were observed for all dyes (Figure 16); a rapid decrease up to approx. 20°C and a slightly reduced decrease above 20°C. Two temperature region ranges were also observed in the transmission. Two groups of dyes can be differentiated: slower fading for RES-035 and RES-006, faster fading for RES-033, RES-034, and UTAD. Using an Arrhenius plot, the activation energy for the fading process of different dyes can be calculated. Interestingly, similar activation energies were observed for different dyes in the low-temperature region despite differences in fading times.

[00182] Conclusively, RES-006 and RES-042 were identified as the best photochromic dyes, and Elastollan® and PDMS were identified as best photochromic dye matrices. Other dyes and matrices also showed very advantageous features.

[00183] Example 7: Impregnation method

Dye uptake by film swelling in organic solvent followed by drying.

Preparation steps:

1. Preparation of 10w% TPU P-8175CL Resamine solution in THF. (TPU solution is slightly milky.)

2. Preparation of 3*10- ³ mol/L TPC-dye solutions in Anisole using TPC-0033 and TPC- 0062.

3. TPU film preparation: a) TPU solution was filled in a clean glass petri dish and was covered with its lid. After 2 days the film was dry and could be peeled off from the glass. The film is hazy (caused by many small bubbles on the backside) and ~110pm thick. b) A 3” native Si wafer was placed in the glass petri dish. The solution was shaken slowly to remove flow marks which were seen on the Si wafer surface, they are probably caused due to the viscosity of the solution. Clear film obtained (no bubbles on backside)

4. Impregnation

About 1x2cm 110μm thick TPU films were placed into both dye solutions for 15min or overnight. When the film was taken out the size was doubled. The wet films were placed on top of a conventional glass MS. After 20min the corners bended and it looked like a contact lens. On the next day the film was again flat but still slightly bended, it shrunk back to its initial size. Homogeneous films with high absorption were obtained. The above described preparation steps were done in the same way but using a 10wt% GPTMS into an Elastollan® 890 Al 0000 solution in THF and subsequent stirring for 1.5h. After impregnation, the films were washed in pure Ethanol and hung up on metal clips for drying before placing them on top of glass substrates for measurement. [00184] The features of the present invention disclosed in the specification, the claims, and/or in the accompanying figures may, both separately and in any combination thereof, be material for realizing the invention in various forms thereof.