Molecular motion in amorphous polymers. Consideration of the mechanism for α, β and (αβ) dielectric relaxations

Abstract

The similarity of the dielectric α process in certain polymers, copolymers and supercooled liquids is discussed. It is shown that the cross correlation terms in the polymer dipole correlation function are a combination of equilibrium dipole correlations and certain time dependent correlations for a reference dipole in a chain. Under certain circumstances the time dependence of each cross correlation term is simply given by the vector autocorrelation function for a reference dipole in the chain. It is suggested that this is the case for the polymer systems considered, and further, that the microbrownian motions in polymers are cooperative motions of a kind observed in supercooled liquids, and give non-exponential correlation functions in time which may not be regarded in terms of a distribution of relaxation times.