Density fluctuations in glassy poly(ethylene terephthalate).: Influence of the thermal treatment

The dependence of the time scale for electron density fluctuations upon the nature of the starting glassy poly(ethylene terephthalate) (PET) was studied. X-ray scattering experiments were performed to examine the influence of the nature of the glassy state, previously induced by heat treatment, on the cold crystallization features from the glass. The time scale for electron density fluctuations prior to cold crystallization of PET strongly depends on the local arrangement of polymer chains within the glassy state induced by the different heat treatments of the starting material.