| Abstract: | Differential scanning calorimetry and thermomechanical analysis are used for examining the thermal behaviour of amorphous poly(ethylene terephthalate) films in the glass-transition range. By variation of the heating rate between 0,2 and 100 K. · min?1, it is possible to obtain either an exotherm associated with a shrinkage, or an endotherm, or both of these phenomena. It is found that very low heating rates not only give rise to a retardation mechanism but also to a molecular rearrangement. |
