Refractive Indices and Molecular order in 4,4′Bis (Pentyloxy)azoxy Benzene in the Nematic State

The refractive indices and densities of 4,4Bis(pentyloxy)azoxy benzene [CH3(CH2)4OC6H4N:N(:O)C6H4O(CH2)4CH3] have been measured in the crystalline, nematic and isotropic phases. The orientational order parameters and polarizabilities in the mesophase have been evaluated by Neugebauer's approach for several temperatures and wavelengths. The order parameter at the same temperature for different wavelengths turns out to be same. The universal curve of the order parameter is given.