Orientation and conformation in PET: New information from specular reflection FT-IR

Specular reflection FT-IR spectroscopy was used to study thick films of amorphous poly(ethylene terephthalate) that had been subjected to either uniaxial drawing or thermal annealing. The high qualify of the spectra made it possible to perform, for the first time, a detailed analysis of the most intense absorption bands. Curve-fitting techniques were used to decompose these bands into individual component peaks, and the effect of drawing upon the intensity and dichroism of these peaks was analysed. The results provide new insight into the conformational and other structural changes that occur upon drawing and thermal annealing of PET.