Thermal stability and crystallization kinetics in superionic glasses using electrical conductivity–temperature cycles

Abstract

The present work demonstrates application of electrical conductivity (σ)–temperature (T) cycles to investigate thermal properties viz., crystallization and glass transition kinetics in AgI–Ag2O–V2O5–MoO3 superionic glasses. The σ–T cycles are carefully performed at various heating rates, viz., 0.5, 1, 3, 5, and 7 K/min. The conductivity in Ag+ ion conducting glasses exhibit anomalous deviation from Arrhenius behavior near glass transition temperature (Tg) followed by a drastic fall at crystallization (Tc). The temperature corresponding to maximum rate of crystallization (Tp) is obtained from the derivative of σ–1/T plots. With increasing heating rates, the characteristic temperatures (Tg, Tp) are found to be shifting monotonically toward higher temperatures. Thus, activation energy of structural relaxation Es, crystallization Ec and other thermal stability parameters have been obtained from σ–T cycles using Kissinger equation and Moynihan formulation. For a comparative study, these kinetics parameters have also been calculated from differential scanning calorimetry plots. The parameters obtained from both the methods are found to be comparable within experimental error.