| Реферат: | eng: The temperature dependences of alpha relaxation time tau(alpha)(T) of three glass-forming liquids (salol, o-terphenyl, and alpha-picoline) were investigated by a depolarized light scattering technique. A detailed description of tau(alpha)(T) near T-A, the temperature of the transition from the Arrhenius law at high temperatures to a non-Arrhenius behavior of tau(alpha)(T) at lower temperatures, was done. It was found that this transition is quite sharp. If the transition is described as switching from the Arrhenius law to the Vogel-Fulcher-Tammann law, it occurs within the temperature range of about 15 K or less. Most of the known expressions for tau(alpha)(T) cannot describe this sharp transition. Our analysis revealed that this transition can be described either as a discontinuous transition in the spirit of the frustration-limited domain theory [D. Kivelson, G. Tarjus, X. Zhao, and S. A. Kivelson, Phys. Rev. E 53, 751 (1996)], implying a phase transition, or by a phenomenological expression recently suggested [B. Schmidtke, N. Petzold, R. Kahlau, M. Hofmann, and E. A. Rossler, Phys. Rev. E 86, 041507 (2012)], where the activation energy includes the term depending exponentially on temperature.
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