SLOW RELAXATION NEAR STRUCTURAL AND ORIENTATIONAL TRANSITIONS IN GLASS-FORMING LIQUIDS AND SOLIDS

We argue that the fragility observed near the glass-transition tempera ture complies with the growing correlation length conception for the e ntire family of glass-forming materials. The analysis is given through the percolation-theoretical treatment of the relaxation dynamics cons idered in an effective medium of dimension (d) over bar. For long-live d clusters of characteristic radius R-0 dynamical correlations are int roduced through the relaxation time tau(0) infinity R-0(z). The relaxa tion function is given in an explicit Kohlrausch-Williams-Watts form w ith the stretch exponent beta = (d) over bar/(z + (d) over bar) that r esults in the fragility m = m(0)(1/beta - 1) It is shown that within t he low-frequency domain the cluster-growing correlations are consisten t with the Dixon-Nagel master curve and fit the idea of universality o f glass-transformation features in solids and liquids.