Glass Transition Characteristics and Thermodynamic Functions of (1–x)(0.75TeO2–0.25WO3) + xLa2O3 Glasses

The temperature-dependent heat capacity of three high-purity (1– x )(0.75TeO 2 –0.25WO 3 ) + x La 2 O 3 tellurite glass samples (x = 0.02, 0.04, and 0.06) has been determined by dynamic calorimetry in the range 320–1000 K. The experimental devitrification and heat capacity data have been used to evaluate standard thermodynamic functions: C p o ( T ), enthalpy, entropy, and Gibbs energy in glassy and supercooled liquid states. We have demonstrated model-parameter similarity of properties in a statistical approach and found correlation relationships for parameters as functions of composition, which make it possible to predict the thermodynamic functions of unexplored glasses of this series. We have identified crystallization-resistant compositions of (1– x )(0.75TeO 2 –0.25WO 3 ) + x La 2 O 3 glasses as a basis for the development of optically active elements.