A FREE-ENERGY LANDSCAPE MODEL FOR PRIMARY RELAXATION IN GLASS-FORMINGLIQUIDS - ROTATIONS AND DYNAMIC HETEROGENEITIES

Higher order correlation functions as observed in four-dimensional NMR experiments on glass-forming liquids are interpreted in terms of a si mple model for molecular reorientations. Its key assumption is an intr insic link between the rotational and structural relaxation of the liq uid. It is shown that the introduction of an additional time scale as proposed previously is not necessary. Furthermore the model naturally accounts for a number of features associated with rotational motions i n supercooled liquids. Applications of the model to other aspects of t he alpha relaxation in supercooled liquids are discussed. (C) 1997 Ame rican Institute of Physics. [S0021-9606(97>51247-5].