On the coupling in molecular motions: A novel molecular microstructure approach to the physical meaning of the Ngai's coupling parameter

The dielectric behaviour through DETA system has been studied for six PVC s amples of distinct molecular microstructure in terms of content and associa ted surroundings and conformation of the local configurations mmr termini o f isotactic sequences. Both the dielectric studies and the microstructure o f the samples, as obtained by stereospecific substitution reaction of an ad ditive-free commercial PVC are to be published in detail separately. For pu rposes of clarity some of the results are mentioned in Experimental section . The phenomenological correlation between the beta parameter as defined by N gai's theory and the microstructure of the samples, quantities both issued from the above quoted work, is considered in the present paper with the obj ective of providing some novel ideas on the physical meaning, at molecular level, of the Ngai's coupling parameter, in the light of mobility constrain ts and local free volume associated with mmr structure at its likely confor mations.