Studies of Molecular Motion of Chiral Smectic Liquid Crystals by ^<13>C NMR Spin-Lattice Relaxation Time Measurement

Abstract

In order to discuss the molecular fluctuation in chiral smectic phases, the temperature dependence of the spin-lattice relaxation time (T_1) was measured using ^<13>C-NMR in MHPOBC and DOBAMBC. In the SmC_A phase of MHPOBC, the relaxation time (T_1) of phenyl group decreased with increasing temperature until it attained a minimum at 95℃, and then increased. At, the temperature of T_1 minimum, the correlation time of the molecular motion, which dominates T_1, could be estimated at about 10^<-9> s.