Temperature-dependent study of carbon-13 spin-lattice relaxation times in para -azoxyanisole-A nematic liquid crystal

Abstract

The ¹³C spin‐lattice relaxation times of both the ring and methyl carbons in the liquid crystal, p‐azoxydianisole, are reported as a function of temperature on both sides of the clearing point. In marked contrast to earlier results on proton relaxation, the relaxation times were found to exhibit no noticeable discontinuity at the nematic‐isotropic transition temperature. The results are explained by comparing the mechanisms influencing the carbon‐13 T₁'s to those present for proton relaxation.