Solubility ofp-phenylazophenol in low molecular weight liquid crystalline precursors

Freezing point temperatures for binary mixtures containing phenylazophenol (PAP) with p-(p-methoxyphenylazo)phenol (MOPAP), p-(p-ethylphenylazo)phenol (EPAP) and p-(p-ethoxyphenylazo)phenol (EOPAP) have been experimentally determined using differential scanning calorimetry. Enthalpies and entropies of fusion for the four phenylazophenol derivatives were also measured. Results of these measurements indicate that the three binary systems exhibit only slight deviations from ideality at temperatures between the melting points of the pure components. Deviations become more pronounced in the PAP+EOPAP system as the temperature decreases below the melting pont of the ethoxy-derivative.