Thermal activation of dipolar relaxation

In order to progress further in the interpretation of dipolar relaxation behaviour we must develop a molecular model in still more detail. Many different models, depending on the type of material concerned, have been proposed anji these have led to a large number of theoretical treatments. We shall confine ourselves to two theories, which are particularly relevant to polymers, and provide a suitable basis for general discussion of the main features encountered. First, in this section, we will consider the theory which has been central to the understanding of the temperature dependence of nearly all reaction rate processes thermal activation over a potential-energy barrier. 

This equation, an example of the well-known Arrhenius law, means that a plot of lnr against l/T should give a straight line whose slope is directly related to the activation energy. 

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