PURPOSE: To obtain a glass form having a complex shape which can not be obtained in a conventional method by using a casting mold wherein one part equivalent to a core is made of a mold material capable of being fluidized and allowing sol to gel in the casting mold and thereafter fluidizing the casting mold in a gelling process.
CONSTITUTION: As a mold material (hereinafter expressed as a core material) capable of being fluidized, the material having m.p. in a range within the temp. capable of holding the fluidization of sol and being insoluble in sol in a solid phase is used and as a fluidizing means, a heating and dissolving method is adopted. Sol 4 is introduced into a casting mold 1 manufactured with both core 2 made of the core material and outer mold 3 and allowed to gel to obtain gel 5 (figure (b)). Then after fluidizing the core 2 and allowing sol to gel (figure (c)), the temp. is raised at fluidizing temp. or more together with the casting mold 1 to melt the core 2. Thereafter the temp. is held at the fluidizing temp. or more until gel 5 is taken out from the casting mold 1. As a result, even if gel 5 discharges syneresis water 6 and shrinks with age, strain is not caused in gel 5 by means of the fluidized core material 7 and therefore gel 5 is not cracked.
IKEJIRI MASAHISA
AOKI MIKIO
