On Dielectric dispersion and conductivity behaviour of polyvinyl butyral and polymethyl trifluoro propyl siloxane

Empirical formula suggested by Kita and Koizumi for evaluating the magnitud e of dielectric dispersion from dielectric loss data in a limited range of frequency around the relaxation frequency for the Cole-Cole relaxation has been examined for poly vinyl butyral (PVB) having degree of polymerisation n of 1600, 900 and 300. Dielectric dispersion behaviour has been discussed in terms of the calculated parameters from the observed frequency maxima. T he ac conductivity to), associated with dielectric dispersion has also been evaluated for three grades of PVB. Another polymer, namely poly methyl tri fluoro, propyl siloxane for which the experimental data were taken from the work of Baired with Sengupta ill the frequency range 100 Hz - (sic)5 kHz a nd (sic) - 100 kHz respectively at varying temperature has also been examin ed for its conductivity behaviour. A con;elation of sigma with frequency an d temperature has been discussed in terms of various models.