Determination of the order parameter of 4-(trans-4'-n-heptyl-cyclohexyl)isothiocyanato-benzene by means of dielectric relaxation spectroscopy

Studies of the dielectric relaxation were made for the isotropic and nematic phases of 4-(trans-4'-n-heptylcyclohexyl)isothiocyanatobenzene, (C/sub 7/H/sub 15/-C/sub y/H/sub x/-Ph-N=C=S) (7CHBT) in the frequency range from 100 kHz to 1 GHz. In the nematic phase two relaxation processes were recorded for the dielectric permittivity component measured parallel to the molecular orientation (director n/spl I.oarr/) and three relaxation processes for the perpendicular permittivity component. The elementary contributions to the total dielectric absorption are found to be of the Debye-type. The strength of the nematic potential and the nematic order parameter as a function of temperature were estimated. The results obtained were compared with the predictions of the Maier-Saupe theory.