Vogel-Tamman-Fulcher behavior

To see more clearly the temperature effect on ion conduction, the logarithmic molal conductivity was plotted against the inverse of temperature, and the resultant plots showed apparent non-Arrhenius behavior, which can be nicely fitted to the Vogel— Tamman-Fulcher (VTF) equation ... 

Experimental measures of molecular mobility within glasses have proven technically difficult because of the long time spans required. General behavior is described by the Vogel-Tamman-Fulcher (VTF) Model, valid for temperatures near Tg, where viscosity increases in a double exponential relationship with decreasing temperature (Angell, 1991) ... 

Figure 11.7 shows the viscosity of the NS2 liquid at ambient pressure as a function of inverse temperature, and it can be seen that the computed value [107] is in very good agreement with experimental measurements from Bockris et al. [108] and from Neuville [109]. To gain additional insight into the relaxational behavior, we use a functional form for the viscosity-temperature behavior given by the Vogel-Fulcher-Tamman law [111] ... 

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