Figures 2c and 2e show the effect of annealing time from 5 to 15 hat 180°C. The height of the peak due to molecular movement above T decreased as the annealing time increased. A longer annealing time resulted in more thermal degradation of the matrix, which retarded the molecular movement above T. This effect due to a change of the extent of thermal degradation is also supported by the effect of annealing temperature, as shown in Figs 2c and 2d. A higher annealing temperature is likely to enhance the extent of thermal degradation, thus resulting in a decrease of the height of the peak associated with molecular movement above T. Since the tail is more pronounced for samples with a larger extent of thermal degradation, as shown in Figs 2d and 2f, it may be attributed to the lower molecular mobility due to extensive thermal degradation.