Temperature dependence of the elastic properties of lead-borate glasses using Brillouin spectroscopy

Abstract

Macroscopic elastic properties of different compositions of lead-borate [xPbO:(1-x)B2O3] glasses were investigated in the temperature range from 293 to 1173 K using Brillouin light scattering technique. Temperature dependence of the sound velocities of each of the glass composition remains almost constant in the glassy state and exhibit a rapid reduction in velocity above the glass transition temperature, Tg. The slopes of the temperature-dependence of the sound velocities above Tg infers the fragility in the glass-forming liquids, and exhibits a decreasing trend for x > 0.4. The scaled sound velocities within the glassy regime were found to fall on two separate master curves: one for the samples with 0.2 ≤ x ≤ 0.6, and another with x = 0.7, 0.8. This shows that the variation of the glass structure with temperature varies uniquely for the first and second set of samples. It further implies that the temperature dependence of the elastic behaviour within the glassy state is independent of the amount of modifier up to x = 0.6, and marks the regime in x above which the Pb–Pb correlations increase and PbO acts as a glass former. The first set of samples exhibits the presence of residual stresses owing to more open-volume structure compared to the second set of samples which do not exhibit residual stresses.