Electron resonance study of the perturbation of the order in a nematic mesophase by a second component

The degree of alignment of a paramagnetic probe, vanadyl acetylacetonate, has been measured as a function of temperature in mixtures of p-azoxyanisole with various non-mesomorphic solutes. Although the addition of the solute results in a large depression of the isotropic-nematic transition point, the alignment of the probe is largely unaffected. This suggests that the presence of the solute does not seriously disturb the highly-ordered structure of the mesophase. This view is confirmed, or the degree of alignment of the probe at the same reduced temperature is independent of either the solute or its concentration.