Glass transition activation energy, glass-forming ability and thermal stability of Se 90In 10−xSn x ( x=2, 4, 6 and 8) chalcogenide glasses

Abstract

Differential scanning calorimeter (DSC) has been employed to investigate the glass transition activation energy E t, thermal stability and the glass-forming ability (GFA) of Se 90In 10− x Sn x ( x=2, 4, 6 and 8) chalcogenide glasses. From the dependence of the glass transition temperature T g on the heating rate β, the E t has been calculated on the basis of Moynihan and Kissinger models. Results indicate that T g and E t attain their minimum values at 6 at% of Sn. Thermal stability has been monitored through the calculation of the temperature difference T c– T g, the stability parameter S, the enthalpy released during the crystallization process H c and the crystallization rate factor K p. The GFA has been investigated on the basis of Hurby parameter H r, which is a strong indicator of GFA, and the relaxation time. Results of GFA are in good agreement with the fragility index F i calculation and indicate that Se 90In 4Sn 6 is the best glass former. The compositional dependence of the above-mentioned parameters was discussed on basis of the topological model of Thorpe and Phillips and the critical composition found to occur at an average coordination number 〈 z〉≈2.36, which is thermally most stable.