Abstract
Boro-tellurite glass system with different concentrations of Bi2O3 had been prepared and characterized. The FTIR analysis indicated a glass former role of Bi2O3 that was deduced from the formation of [BiO3] structural units. These units transformed the structural units [TeO3] into [TeO4] and [BO3] into [BO4]. This process increased the environment of bridging oxygens that increased the density and decreased the molar volume of the glass structure. The increase of the ultrasonic velocities, the elastic moduli (experimentally determined and theoretically computed according to Makishima-Mackenzie model) with the addition of Bi2O3 was attributed to the increased compactness and rigidity. The increment coordination number increased the cross-link density and improved the glass transition temperature. The hyper-polarizability of Bi3+ due to the d-orbital contribution increased the crystallization peak and enhanced the thermal stability.