Secondary relaxation non-Arrhenius temperature dependence

Although the existence of "polyamorphism is debatable, heterogeneity is inherent in an amorphous system (29-31). Amorphous. systems, in addition to exhibiting cooperative primary or a-relaxations and non-cooperative secondary or p-relaxations, may reveal multiple secondary relaxations (32). These different relaxation processes are likely to have different temperature dependences, e.g., a-relaxations are generally described by the VTF or WLF models whereas the Johari-Gold,stein relaxations are usually de.scribed by Arrhenius model (27). 

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