Anisotropic properties of nematic p-n-alkanoyloxy-p '-nitroazoxybenzenes

The temperature dependences of the density and refractive indices of the ne matic and isotropic phases of p-n-alkanoyloxy-p'-nitroazoxybenzenes were me asured. The effect of the hydrocarbon chain length on the density, on the m agnitudes of the jumps in the molar volume for nematic phase-isotropic phas e transitions, and on the coefficients of the molecular packing of mesomorp hic substances was examined. Based on double refraction measurements, the e ffective, polarizability, anisotropy, molecular polarizability, and the deg ree of orientational ordering of the nematic phase were calculated. It was shown that the molecular polarizability increases, and the degree of orient ational ordering decreases with increasing length of the alkyl substituent.