Relaxation theories of the glass transition and viscous flow of glass-forming melts are presented. The main attention is devoted to modern representations of the glass transition equation qτ_g = δT_g determining the appearance of a glassy state during cooling. Here, q=d T/dt is the temperature change rate during melt cooling and τ_g is the relaxation time at the glass transition temperature T_g. Various methods for calculating the characteristic temperature band δ T_g during the liquid—glass transition are considered. The generalized equation for the dependence of T_g on the melt cooling rate is derived. Based on the model of delocalized atoms, the modified kinetic glass transition criterion is discussed. The generalized viscosity equation for glass-forming liquids is derived.

Keywords: glass transition, amorphous polymers, inorganic glasses, metal amorphous melts, glass transition equation, viscosity, glass transition criterion, relaxation theories PACS: 61.43.Gt, 64.70.Q−, 81.05.kf (all) DOI: 10.3367/UFNe.2018.04.038319 URL: https://ufn.ru/en/articles/2019/2/a/ 000466030200001 2-s2.0-85067549795 2019PhyU...62..111S Citation: Sanditov D S, Ojovan M I "Relaxation aspects of the liquid—glass transition" Phys. Usp. 62 111–130 (2019) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Received: 17th, January 2018, revised: 27th, March 2018, accepted: 11th, April 2018 Оригинал: Сандитов Д С, Ожован М И «Релаксационные аспекты перехода жидкость—стекло» УФН 189 113–133 (2019); DOI: 10.3367/UFNr.2018.04.038319