Isothermal structural relaxation: temperature and time dependencies of relaxation parameters

Abstract The isothermal structural relaxation has been studied on model glass with well-defined thermal history by differential scanning calorimetry (DSC). The computer modeling of DSC scans was based on Tool–Narayanaswamy–Moynihan model with Kohlrausch–William–Watts relaxation function. The parameter of non-exponentiality, β, and the enthalpy change, ΔH, have been evaluated and their time and temperature dependencies have been discussed. It was found that β is both temperature and time dependent. When the relaxed glass has reached equilibrium the corresponding limit enthalpy change, ΔHeq, was found to be less than difference between glassy state and corresponding liquid state obtained by linear extrapolation of its ΔH vs. T dependence below the glass transition temperature.