Dynamics of Nematic Liquid Crystal with Quenched Disorder in the Random Dilution and Random Field Regimes

By means of specific heat spectroscopy, we have studied the dynamics of nematic 8CB nucleated, in the presence of random disorder, as the temperature is lowered across the isotropic to nematic phase transition such that the crossover region of random dilution to random field regimes of disorder strength is explored. We show, in terms of frequency dependence, hysteretic behavior, and aging effects, that the out-of-equilibrium properties of the nematic nucleated in the random disorder regime are strongly reminiscent of the bulk material while the one grown in the random field regime shows a glassy behavior with aging leading to slower dynamics. The aging effect has been explained in terms of strain relaxation in analogy with observations in other soft glassy colloidal systems.