Аннотация:Physical-chemical nature of glass transition process
V.S.Minaev12, S.P.Timoshenkov2, V.P.Vasiliev2, V.V.Kalugin2, D.Zh.Mukimov2
1Research Institute of Material Science and Technology, Russia;
2National Research University of Electronic Technology, Russia 3 Lomonosov Moscow State University, Chemical department
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 glass-forming 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 inter-transformation of polymorphoids of different PMs (LTPM into HTPM in interval Tm...Tw-rev and HTPM into 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.