Structural aspect of possible interrelation between fragility (length) of glass forming melts and Poisson's ratio of glasses

The analysis of the development of the notion of fragility (length) of glass forming melts and the nature of Poisson's coefficient of glasses is presented for the period from 60s of 20th century, basing on structural relations. It is shown that the most distinct structural correlations have been obtained in the framework of ideas of Zachariasen and Hagg, activation theory of viscous flow, and lattice theory of Mie and Gruneisen. It is shown that the existence of universal correlations between fragility and Poisson's ratio is physically baseless yet. The reason is that the systems under comparison are in frozen and in metastable states and the physical meanings of the properties under consideration are incompatible. The possibility of particular correlations between fragility of glass forming melts and Poisson's ratio is discussed. Such correlations possibly exist within special groups of substances which have related structures. The theory of viscous flow for the transition from glass to metastable liquid is refined in the framework of the elastic continuum theory. (c) 2007 Elsevier B.V. All rights reserved.