Properties of Bismuth-Containing High-Silica Glass Depending on the Bismuth Concentration and Heat Treatment. I. Spectral-Optical Properties

Abstract

Bismuth-containing high-silica glass is synthesized by impregnating porous glass matrices in 0.01–0.5 M aqueous solutions of bismuth nitrate with the subsequent heat treatment at a temperature of 50–875°C. The dependences of the spectral-optical properties of the synthesized glass on the concentration of the doped bismuth (0.02–1.17 wt % Bi₂O₃) and heat treatment temperature are studied. It is found using the method of optical spectroscopy that bismuth is present in glass in different oxidation states—Bi³⁺, Bi²⁺, and \(\rm{Bi_5^{3+}}\) clusters. Near infrared spectroscopy in the 7500–4000 cm^–1 frequency range reveals that an increase in the temperature results in a gradual decrease in the intensity of the absorption bands due to the vibration of hydroxyl groups and water molecules adsorbed on the surface. The glasses (T ~ 50 and 400°C) exhibit bands at 4445–4443, 4433, and 4417–4415 cm^–1, which correspond to the absorption of Bi⁺ ions.