Chemical properties of hydrolyzed surface layers on SiO2-BaO-B2O3

Abstract

The leaching process of SiO2—BaO—B2O3 glass in distilled water and the subsequent processes during storage in air were studied to complete the recent investigations on the interaction of SiO2—BaO—B2O3 glass with polishing slurries. The in-depth distributions of hydrogen and glass constituents existing in the leached surface layers were measured using nuclear reaction analysis and Rutherford backscattering spectrometry. Hydrogen uptake, barium loss and redeposition of dissolved zirconium-containing material on the surface occurred during the interaction with water. Changes of the in-depth distributions caused by reactions between the molecular water from the air, the materials of the leached surface layers and the glass components during a subsequent storage in air at room temperature were also observed. The analyses show unequivocally that the chemical driving forces of these reactions exhibit differences which depend exclusively on the different chemical properties of the leached surface-layer materials. These properties are on their part determined by different leaching agents and parameters. Consequences for the control of chemical interactions of silicate glass surfaces during the fabrication of optical surfaces are considered.