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Abstract
The influence of DC and AC electric fields on a melt of copolymer based on poly(ethylene terephthalate) (PET) and p-hydroxybenzoic acid (PHBA) were investigated. Spherulite domains or large-scale schlieren textures have been observed under an AC voltage with an above threshold amplitude depending on the initial state of the LC polymer being partly oriented or strongly scattering small-scale schlieren texture, respectively. The raise times of the texture changes were recorded to be in the range of several hours. The change of the direction of the electric field from normal to transversal using transversal geometry, confirmed the reorientation action of the AC electric field on the nematic director accompanied with the creation of band domains perpendicular to the electric field direction. All textures and light transmission curves obtained with the two geometries clearly indicated the negative value of the dielectric anisotropy of the nematic polymer which is in agreement with other investigations.