RELAXATION PROCESSES BELOW THE GLASS-TRANSITION IN A GESE2-GETE-SB2TE3 ALLOY

The relaxation behavior has been studied of a bulk chalcogenide glass of composition (GeSe2)70(GeTe)15(Sb2Te3)15 prepared by water-quenching or slowly cooling the molten alloy and which was subjected to several thermal treatments. Heat capacity measurements, by differential scanning calorimetry have demonstrated that the undercooled liquid obtained by heating the glass above the glass transition is in an equilibrium state and that slow cooling from this state gives glasses which relax when they are annealed in the glass transition temperature range. The enthalpy and entropy differences between each annealed glass and the undercooled liquid were taken as properties sensitive to the relaxation induced in the glass. These relaxation processes were found to be governed by a distribution of activation energies. The corresponding activation energy spectra characterizing the relaxation proceses at the temperatures in the glass transition region were obtained.