Читать книгу Encyclopedia of Glass Science, Technology, History, and Culture - Группа авторов - Страница 296

Most properties of glasses exhibit rather uninteresting monotonic continuous variations even when r crosses its isostatic value. Only some configurational properties show extremum values with respect to r at the rigidity percolation threshold (i.e. at r* = 2.4). Tatsumisago et al. [30] reported that the configurational heat capacity and the activation energy of viscosity exhibited minima in the Ge–As–Se system at r = 2.4. Similar results were obtained by Senapati and Varshneya [31] in the Ge–Se and Ge–Sb–Se systems. It is worth noting that by investigating a range of Ge–As–Se compositions, all having the same values of r, Wang et al. [24] have reported that values of the configurational properties are not a unique function of r implying that topology alone is not sufficient to determine the variation of properties with composition, effect of chemical disorder must also be considered.