Patent ID: 9746773
Date: 2017-08-29
CPC Classifications: B82Y,C03B,C03C,G03F

Claim:
1. A method of selecting a titania-doped quartz glass having a reduction in OH group concentration of less than or equal to 100 ppm, comprising measuring a sample taken from a titania-doped quartz glass ingot to be selected for OH group concentration, heat-treating the sample of the titania-doped quartz glass ingot at 900° C. for 100 hours, measuring the heat-treated sample for OH group concentration, computing a reduction of OH group concentration to evaluate the sample whether the reduction of OH group concentration is less than or equal to 100 ppm or not selecting the titania-dope quartz glass ingot whose sample had a reduction of OH group concentration less than or equal to 100 ppm and then shaping the selected ingot into a predetermined shape, wherein said titania-doped quartz glass ingot being prepared by a method comprising the steps of subjecting a silicon-providing reactant gas and a titanium-providing reactant gas to oxidation or flame hydrolysis with the aid of a combustible gas and a combustion-supporting gas, to thereby form synthetic silica titania fine particles, depositing the silica-titania fine particles on a rotating target, and concurrently melting and vitrifying the deposited particles into titania-doped quartz glass.