ORDER AND DYNAMICS OF 9,10-DIPHENYLANTHRACENE IN THE LIQUID-CRYSTAL ZLI-1167 - A FLUORESCENCE DEPOLARIZATION STUDY

The behavior of the probe 9,10-diphenylanthracene (DPA) dissolved in t he nematic and isotropic phase of the cyanocyclohexyl mesophase mixtur e ZLI-1167 has been investigated using fluorescence depolarization on the nanosecond time scale. The orientational order parameters and the rotational diffusion coefficients of the fluorescent probe molecule ha ve been determined as a function of temperature together with its fluo rescence lifetimes using the Global Target Analysis method with expone ntial spline interpolating functions. In the isotropic phase of the Li quid crystal the probe dynamics approaches the hydrodynamic behavior u nder slip boundary conditions. A comparison with DPA rotational diffus ion times in other systems is provided.