PET pellets were dissolved in chloroform-trifluoroacetic acid (4.1 vol.). The concentrations of solution were 9 and 12 wt% respectively. A glass plate was inserted into the solution

then taken out and held at different temperature (from room temperature to 100℃) to make the solution cast films of ca. 10μm thick. The absorbance ratio A978/A795 of 973cm-1 and 795cm-1 infrared bands was used to measure the crystallinity of the solution cast PET films. The result shows that the film cast at room temperature was amorphous.