Dipole loss peak distribution

The peak related to the (3-relaxation is rather broad and symmetric. Using the half-height width of the loss peak, it can be four to six decades wide. With increasing temperature, the width of the 3-peak decreases. Quite often the width of the 3-relaxation is modeled by both a distribution of the activation energy and the preexponential factor (in the sense of Eq. 12.27) which might be related to a distribution of molecular environments of the relaxing dipole. In most cases it is difficult to extract information on the basic mechanisms of molecular motion. In other cases the broadness of the 3-peak can be also due to the overlapping of different relaxation processes as demonstrated for polycarbonate (see Fig. 12.11). 

Dipole Relaxation Losses. Up to about 10 Hz, dipole relaxation losses are important. They result from the energy that is given up by mobile ions as they jump over small distances in the network. Dipole losses are greatest when the frequency of the applied field is equal to the relaxation time of the dipole. At frequencies either far above or far below the resonant frequency, the losses are the least. Because of its random structure, glass has more than one relaxation time. This results in a broad distribution of dipole relaxation losses with frequency, rather than one discrete loss peak (see curve 2 in Fig. 2.37). 

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