Viscosity and crystallization mechanism of cesium loaded iron phosphate glasses

Abstract

This paper describes the melt viscosity behaviour and the crystallization mechanism of a series of ironphosphate glasses. High temperature viscosity measurements were carried out on pristine iron phosphateglass and a series of cesium loaded iron phosphate glasses in order to understand the effect of additionof Cs2O on viscosity of iron phosphate glasses. Activation energy of viscous flow was estimated fromthe experimental data by applying Arrhenius model of viscosity–temperature relationship. Activationenergy of viscous flow is observed to be strongly correlated to glass transition temperature of theseglasses. Fragility of iron phosphate and cesium loaded iron phosphate glass systems were also evaluated inregion of high temperature. Crystallization of these glasses was studied using thermal analysis techniques.Temperature integral approximation free method was utilized to evaluate the kinetic parameters such as activation energy of crystallization (Ec) and Avrami exponent (n). The value of Avrami exponent ‘n’obtained showed that the glasses under present study crystallize via bulk crystallization mechanism, i.e.,nucleation and three dimensional growth.