| 摘要 |
PURPOSE:To obtain the title silica glass causing no solarization even exposed to high-energy radiation by heating in a He gas a synthetic silica glass produced by flame hydrolysis to effect degasification. CONSTITUTION:A synthetic silica glass produced by flame hydrolysis is heated in a He gas at >=500 deg.C to effect degasification, thus obtaining the objective synthetic silica glass. This silica glass is 1-1000ppm in OH group content and <=0.1ml/100g in dissolved hydrogen gas. If <1ppm on the OH group content, a ultraviolet absorption peak at 260nm will be developed. On the other hand, in case of >1000ppm in said OH group content, a solarization will occur by increasing the ultraviolet absorption near 170nm. And if >0.1ml/100g in the dissolved hydrogen gas, a solarization will also be developed by increasing the ultraviolet absorption at 180-220nm. |
