| 摘要 |
PROBLEM TO BE SOLVED: To provide a quartz glass for an ultraviolet light, having less reduction of its transmitting rate by an excimer laser light irradiation and exhibiting a small positional change of refractive index, and provide a method for producing the same. SOLUTION: This quartz glass has <=0.1% ultraviolet light transmitting rate reduction after irradiating 106 shot of ultraviolet light pulse laser having >=100 ml/cm2 per 1 shot energy density, within 10-7 change of the positional change of the refractive index for the ultraviolet light, 2.201-2.205 g/cm3 density and <=50 ppm OH group in weight ratio. The method for producing the above quartz glass is provided by sintering a porous synthetic quartz glass material under vacuum or an inert gas, further making it as transparent, heating at >=1,600 deg.C and performing a heat treatment of holding it at a temperature of >=1,000 deg.C and <=1,300 deg.C for >=5 hours during its cooling process.
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