Infra-red and Raman spectra of poly(m-methylene terephthalate) polymers

A detailed comparison of the infra-red and Raman spectra of poly(trimethylene terephthalate) (3GT), poly(tetramethylene terephthalate) (4GT) and poly(ethylene terephthalate) (2GT) is reported. Particular attention has been given to the changes in the spectra which occur on crystallization. Additionally, the spectra of oriented 4GT samples have been examined under applied stress, because this produces a change in the structure of the crystalline regions. It is shown that the differences between the spectra of these polymers can be satisfacorily accounted for by changes in the conformation of the molecular chains involving both trans/gauche isomerism in the glycol sequence and the planarity of the terephthalate residue.