Micro‐rheology and relaxation phenomena in Tg vicinity

The present paper describes possible forms of relaxation phenomena in T_g vicinity. The individual types of relaxation in amorphous matrix are described in the areas of Vogel's temperature, T_g and crossover temperature. Special emphasis is laid on the difference between Flory's relaxation mechanism and the approach by Di Marzio, Adams and Gibbs. These authors used the common formula of Flory, however, their interpretations of the so‐called “configurational phenomena” reflect completely different realities. The theoretical justification of heat capacity as a complex number (recently introduced by Hutchinson, Monserrat and Schawe in T_g vicinity) is provided in detail and compared with the existing experimental evidence quoted by the authors of these contributions as well as with data published in literature. The relation between complex heat capacity and relaxation of internal stress in amorphous matrixes or the effects of ageing are discussed.