Dielectric relaxation as a chemical rate process


Dielectric relaxation as a chemical rate process

Dielectric relaxation was interpreted as a chemical rate process by Walter Kauzmann. According to Kauzmann, relaxation rates may be arranged in two or more distinct groups: "Depending on how rapidly they change with temperature. In one group, we have those rates which depend on properties such as thermal conductivity, electrical conductivity of metallic conductors and the velocities of sound and light which do not vary markedly with temperature. In the other group we have those rates which vary considerably with temperature: the rate at which the portion of the dielectric polarization arising from orientation of permanent molecular dipoles comes in to equilibrium with the applied electric field belongs to this class."

Whenever the rate of a physical process depends markedly on temperature, it is quite certain that at some stage in the process a molecule or the other is forced to wait until it has acquired by thermal fluctuation, a considerable amount of energy in excess of the average thermal energy of the medium. Now the factors which govern the rate of acquiring large amount of energy through thermal fluctuations have long been object of study by chemists so far a s rates chemical reactions are concerned. As present time fairly complete ideas about these factore have been developed, so that we can apply these ideas to explain dielectric relaxation process.


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