Anomalous Brillouin shift in lead-tellurite glass above glass transition

Abstract

Binary lead tellurite (⁠20PbO:80TeO2⁠) glass has been investigated using temperature-dependent Brillouin scattering experiments in a wide temperature range (22-450 °C). The glass transition temperature (Tg) has been identified from the sudden drop in the longitudinal acoustic (LA) mode frequency, suggesting disruption of the network structure and structural relaxations taking place in the supercooled liquid state. The line width of the LA mode also exhibits anomalous broadening above Tg, indicating damping of the acoustic wave caused by the weakening of the glass network structure and subsequent rise in the number of non-bridging oxygens.