ИСТИНА

The analysis of the glass transition process has been carried out on the base of the concept of the polymeric-polymorphoid structure of glass and glassforming liquid of individual chemical substances. The glassforming Se, GeSe2, BeCl2, SiO2, P2O5, H2O and so on in crystal state usually exist in the form of two (or more) polymorphous modifications (PMs) - a high temperature modification (HTPM) and a low temperature (LTPM) - which are stable in certain temperature intervals and undergo the polymorphous transformation at Ttr. Intertransformation temperature of different PM’s polymorphoids in glassforming substance (Tw-rev), named as Tg in 1950s instead of Tamman’s windung temperature Tw is an analogue of Ttr in crystal substance. A liquid substance is formed at melting of HTPM and consists mainly of structural fragments of HTPM and some quantity of LTPM structural fragments that have no translation symmetry (a long-range order) but have short range orders and an intermediate-range order inherent to one or another PM and therefore called polymorphoids. Co-polymerization and intertransformation of polymorphoids of different PMs (LTPM^HTPM in interval Tm...Tw-rev and HTPM^LTPM below Tw-rev) at cooling of a liquid substance is the main reason of formation of the nanoheteromorphous glass. Concentration ratio of different PM polymorphoids (CRP) change accompanies the process of vitrification from Tm to Tamman’s Tg - temperature of transformation of viscous-flow liquid into brittle solid glassy state.