REFRACTIVE-INDEXES, CALCULATED ORIENTATIONAL ORDER PARAMETERS, AND POLARIZABILITY ANISOTROPIES OF LIQUID-CRYSTALLINE 3-(4-ALKYL-PHENYLOXY)-PROPANE-1,2-DIOLS

For a novel variant of smectic structures the S(A)+ phase of the homologous 3-(4-alkyl-phenyloxy)-propane-1,2-diols the refractive indices n(e) and n(o) were measured in dependence on the temperature. The polarizability anisotropy, the orientational order parameter, and the packing fraction were calculated using a mean field fitting method. The components of the internal field tensor were included in the fitting procedure. The increasing mobility of the alkyl chain for higher homologues reduces the orientational order in the smectic layers and also the birefringence which is very small. The molecular polarizabilities are increasing nearly linearly with the elongation of the alkyl chain. The small alternation of the polarizabilities corresponds to the alternating change of the length-to breadth ratio. The calculated packing fractions are enhanced for higher homologues.