INTERRELATIONSHIP AND COMMON NATURE OF THE BETA-RELAXATION AND THE GLASS-TRANSITION IN POLYMERS

The work concerns a study of the relationship between beta and alpha transitions in polymers and oligomers, and of the character of the cooperative motion in the alpha transition by means of DSC. The segmental motion in chains arises with beta transition by means of the quasi-independent segment displacements in free volume points. From the standpoint of this concept the beta transition in a certain sense can actually be regarded also as a 'low-temperature tail of the glass transition'. The physical aging and enthalpy relaxation, depending on the test temperature, is controlled preferentially by the alpha -, 'intermediate', or beta -relaxation process.