MODEL THEORIES OF THE INTERACTION BETWEEN STRUCTURAL AND LOCAL ORIENTATIONAL RELAXATION PROCESSES IN POLYMERIC SYSTEMS

Local orientational processes in polymer chains in bulk polymer system s may be coupled with local structural rearrangements (free volume flu ctuations, local disordering, the rearrangements in the neighbouring c hains) which could be by itself inactive in mechanical, dielectric or polarized luminescence relaxation processes. A model site theory of th e coupling between structural and orientational properties is applied to the problem of the interconnection between alpha- and beta-processe s in the isotropic and anisotropic polymeric systems (including LC-pol ymers). The coupling for every normal mode of the polymeric chain is d etermined by the relation between at least three principal times: thos e of structural rearrangement from immobile to mobile local state, the time of decay of mobile state and the characteristic time of orientat ion in the mobile state.