FOURIER-TRANSFORM RAMAN-STUDY OF THE CONFORMERS IN POLY(ETHYLENE-TEREPHTHALATE)

Fourier transform (FT) Raman spectroscopy has been proved to be an ade quate technique for the study of the quantitative structural changes w hich take place in poly(ethylene terephthalate) on annealing. The two- phase conformational model proposed previously in the infrared domain using photoacoustic FTIR has been extended to the Raman domain. Moreov er, typical Raman spectral changes with the thermal process have been directly related to conformational rather than crystallinity changes. The correlation between the percentage of the trans isomer obtained by FT-Raman and skin layer crystallinity values obtained by differential scanning calorimetry allows the crystalline and amorphous trans isome r contents to be obtained and their evolution with the annealing proce ss to be followed.