Variation of the entropy of the transition in nematic mixtures

The temperature variation of orientational order parameter in binary mixtur es of two nematic compounds viz P-(p-ethoxy-phenylazo) phenyl Valerate (EPP V) and N-(p-propoxybenzylidene)p-pentylaniline (PBPA) has been estimated us ing refractive index and density data. The higher order parameter <p(4)> ha s been estimated. Employing the Humphries-James-Luckhurst theory the entrop y of the transition of the mixtures at different concentrations has been co mputed. It is observed that the increase in the value of entropy of the tra nsition is associated with the increase in the pair potential of the molecu les in the mixtures.