Symmetry of Orientational Order Fluctuations about the Nematic-Isotropic Phase Transition: An ESR Study

The ESR relaxation of a weakly aligned spin probe dissolved in N-[$p$-methoxybenzylidine]-$p$-butylaniline has been studied near $T_c$, the isotropic-nematic transition. Spin relaxation due to critical orientational fluctuations is observed on either side of $T_c$ and is characterized by a symmetry about $T_c$ that is rather well explained by simple Landaude Gennes mean-field theory for the weak first-order transition.