The thermal crystallization from the glassy state of different samples
of Poly(ethyleneterephthalate) (PET) was investigated with different
techniques, such as infrared and x-ray analysis and polarized optical
microscopy. The different samples of PET were obtained by ageing the g
lassy PET films at room temperature and at 60 degrees C; the behaviour
of these films was compared with that of the fresh sample, put at the
crystallization temperature as soon as prepared. The temperature of c
rystallization was 120 degrees C. All the techniques, investigated to
follow the crystallization phenomenon, show that the fresh sample crys
tallizes with longer times than the others. This result was correlated
with the initial structural organization of the glassy amorphous film
s.