SYNTHETIC SILICA GLASS AND PRODUCTION THEREOF

摘要

PURPOSE:To reduce structural defects by synthesizing silica glass in the presence of H2 in excess of the stoichiometrically required amount based on O2 and heat treating the resultant synthetic silica glass in a non-reducing atmosphere or under vacuum at a specified temperature. CONSTITUTION:SiCl4 is hydrolyzed in an oxyhydrogen flame using H2 in excess of the stoichiometrically required amount based on O2 (H2/O2=2.2-2.5) to obtain a synthetic silica glass. The resultant synthetic silica glass is heat treated in a nonreducing atmosphere such as He, N2, Ar or air or under vacuum at 200-1200 deg.C for prescribed hours, thus obtaining the objective synthetic silica glass free from 650nm red color emission due to irradiation with KrF excimer laser (248nm) and ArF excimer laser (193nm) and free from 280nm light emission due to irradiation with ArF excimer laser (193nm).