ИСТИНА

A general concept of the polymer nanoheteromorphic structure and relaxation of the glass-forming substance considers the glass forming of one and multi-component systems [1]. In the particular case, the concept of polymer-polymorphoid structure and relaxation of the one-component glass-forming substance is explored. One-component glass and glass-forming liquids are constructed from copolymerized polymorphoids (Ps) of varying degrees (or in other words from nanofragments of crystal structures of different polymorphic modifications (PM)) with no translational symmetry (long-range order), but having short-range and intermediate-range orders. The Ps may be absent in a glass containing more than one component (non-polymorphoid glass). The main feature of glass, having various Ps of different PMs, is their interconversion. It is an analogous interconversion of the polymorphic modifications in the crystalline substance. This feature permits to carry out a quantitative structural nano-diagnostic of glass, and to determine the concentration ratio of Ps of different PM’s in S, Se, B2Se3, GeS2, GeSe2, As2S3, As2Se3, SiO2, GeO2, H2O, BeCl2 etc. The Ps of various polymorphic modifications with a concentration ratio depending on the temperature of the melt are forming at the melting of the crystalline substance, which is capable to exist in the form of different PM’s. The melt passes upon cooling firstly at an interval from the melting point Tm to an interconversion temperature of crystalline polymorphic modifications Ttr. In this range the unstable Ps of the low-temperature polymorphic modification (LTPM) are transforming here into the Ps of high-temperature PM’s (HTPM): LTPM → HTPM. In this range the HTPM crystallization is possible upon a slow cooling or annealing. The reverse of the interconversion direction of the Ps (HTPM → LTPM) occurs upon further cooling of the melt at a bending temperature on the "property - temperature" curve. Here the conversion process of the unstable HTPM Ps into the LTPM ones passes lower than the temperature, denoted as Tamman’s Tw. Tamman’s temperature Tw has been unduly replaced by the glass transition temperature Tg. Tamman’s temperature Tg is below than Tamman’s temperature Tw. Now, the reality of Tamman’s temperature Tg convincingly is confirmed by the discovery of the pre-endothermic effect, preceding at heating the "modern» Tg. It is proposed to denote the reverse temperature of the Ps (HTPM↔LTPM) as Tw-rev instead of "modern» Tg. This will reflect Tamman’s role in the introduction of this term into the scientific literature and the physico-chemical nature of the processes occurring in glass at this temperature. The process of the HTPM → LTPM Ps transformation is continuing at a temperature less than Tamman’s Tg (pre-endothermic effect temperature). This process is the physico-chemical basis of the glass aging. It ends after a certain time by the LTPM crystallization within a period of some minutes to millennia for the various compositions. [1] V.S. Minaev, in: Semiconducting Chalcogenide Glass I, Ser. Semiconductors and Semi-metals, v.78, Elsevier Academic Press, Amsterdam, N-Y, Tokyo, 2004, pp. 139-179.