Free rotation of simple molecules and characteristic temperatures in glassy polymers

Purely rotational spectra of CO and HCl molecules added as a probe to polypropylene (PP) and polyvinyl chloride (PVC) were obtained and analyzed. It is shown that the shape of the bands of these spectra, which reflects the degree of disturbance of the rotational motion, is strongly influenced by the local dynamics of the polymer matrix. From the change in the integrated intensity of absorption with the temperature were found temperatures of the transition from free rotation of CO and HCl molecules to their libration, as well as the temperatures of the onset of defrosting of the conformational mobility of the chains of PP and PVC macromolecules.