Correlation between the structure and structural relaxation data for (GeSe2)(y)(Sb2Se3)(1-y) glasses

Abstract

Combined calorimetric and structural study, employing the techniques of differential scanning calorimetry and Raman spectroscopy, was performed to describe the enthalpy relaxation processes in the (GeSe2)(y)(Sb2Se3)(1-y) chalcogenide glasses. The full glass forming compositional region (y = 0.3-0.9) was explored. The enthalpy relaxation was described in terms of the phenomenological Tool-Narayanaswamy-Moynihan model. Compositional evolution of the glass transition temperatures and relaxation activation energies was explained based on the changing average bond energies and overall interconnectivity of the glassy matrices. Resemblance between the activation energies of the relaxation processes and viscous flow was confirmed for all studied glasses. Non-linearity and non-exponentiality of the enthalpy relaxation were found to be invariant with composition. The structural relaxation kinetics as well as kinetic fragilities determined for the present (GeSe2)(y)(Sb2Se3)(1-y) glassy system were very similar to the results obtained earlier for the (GeS2)(y)(Sb2S3)(1-y) glasses, which can be attributed to the similarly constrained topology of the pseudo-binary compositional lines.