Simulation of the glass transition and physical ageing

A kinetic model simulating the glass transition and enthalpic relaxation in poly(3-hydroxybutyrate) is introduced. The model is based on the concept t hat enthalpic relaxation or physical ageing is a continuation of the glass forming process and uses the KWW function to describe the glass formation p rocess and the subsequent ageing of the glass. Non-linearity is introduced by incorporating a dependence of the relaxation time on the fictive tempera ture. The effects of non-linearity on the distribution of relaxation times and the physical ageing process are investigated together with the developm ent of the endothermic ageing peak at the glass transition with increasing extents of ageing. (C) 2001 Elsevier Science Ltd. All rights reserved.