Dielectric Studies of a Series of Liquid Crystalline Pyridine Derivates
نویسنده
چکیده
Measurements of the temperature and frequency dependence of dielectric constants have been performed for five homologues in the range 100 Hz 10 MHz. These substances exhibit a negative anisotropy of the dielectric constants and two relaxation regions (rotation of the molecules around the short resp. long axis) in the investigated frequency range. Even in the crystalline state dipolar reorientations are possible which have been interpreted as rotations of the alkoxy group. Changes of the static dielectric constants, relaxation frequencies and transition entropies are discussed as a measure of structural changes passing the several liquid crystalline phases.
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