PURPOSE: To obtain a quartz glass capable of suppressing fluorescent phenomenon in irradiation by 254nm ultraviolet ray, by applying thermal shock to the quartz glass prepared by sol-gel method so as to converge around strain removing temperature.

CONSTITUTION: When a quartz glass is produced by heating the quartz glass or quartz glass precursor prepared by sol-gel method and maintaining the heated quartz glass for definite time, thermal shock is applied to the resultant quartz glass several times so as to converge around the strain removing temperature. In the production of the quartz glass, the strain is removed by adding thermal shock near strain removing temperature to the quartz glass to reduce structure defects seem to be caused by the strain. The resultant quartz glass has effect suppressed in fluorescent phenomenon occurring when 254nm ultraviolet ray is irradiated and is applicable to use in short wavelength area for optics in the future.