Test and Analysis of Hydroxyl Group in CVD Synthetic Silica Glass

Hydroxyl group, as one of the main impurities of CVD synthetic silica glass, affects glass structure and performance. IR absorption spectra of CVD synthetic silica glass prepared with different carrier gases, H2 and O2, shows different hydroxyl group distribution, it indicates that carrier gas has an important influence on hydroxyl group distribution. Combined the MAS-NMR testing results with the distribution results, the function of homogenization process has been discussed. The results indicate that: hydroxyl group distribution presents a parabolic figure when H2 is the carrier gas, while when O2 is the carrier gas, the distribution presents an inverse parabolic figure; During homogenization process, different structures of hydroxyl group acting with each other, leading to an average distribution of hydroxyl group.