Non-isothermal crystallization kinetics of K2O modified sodium-phosphate glasses

Glasses of composition 55P(2)O(5)-(45-x)Na2O-xK(2)O; (5 <= x <= 25) have been prepared by melt-quench technique. The broad halo in all quenched samples indicates their amorphous nature as confirmed by X-ray powder diffraction. The mixed glass modifiers effect (MGME) on crystallization and thermal stability are investigated using the differential thermal analyzer under non-isothermal conditions. The kinetic of crystallization has been studied using Kissinger's and Augis-Bennett models. The activation energies for glass transition (E-g) and crystallization (E-c) are observed maximum for 10 and 20 mol% K2O glasses. 10 and 20 mol% K2O contained glasses exhibit minimum crystallization frequency than other glasses, which indicate their higher kinetic and thermodynamic stability. FTIR and Raman analysis confirmed the higher polymerization of phosphate groups in 10 and 20 mol% K2O glasses as compared to other glasses. (C) 2016 Elsevier B.V. All rights reserved.