EFFECTS OF DYE DOPING ON FERROELECTRICITY IN VINYLIDENE FLUORIDE AND TRIFLUOROETHYLENE COPOLYMERS

The effects of dye doping on ferroelectricity in vinylidene fluoride a nd trifluoroethylene copolymers have been investigated mainly through dielectric and switching measurements. Large dielectric relaxation, wh ich cannot be explained by dipole fluctuations of individual chain mol ecules around their axes, was observed in the dye-doped copolymer film s. With increasing dye content in copolymers, the relaxation times inc rease, and the dielectric relaxation strength becomes large. However, the switching times and the switching curve are nearly independent of dye content. These results can be explained if we assume that dye is d oped into noncrystalline regions but not into crystalline regions, and forms a long and slender phase boundary in which the dye content is h igh.