UV-VISIBLE LINEAR DICHROISM OF NAPHTHALENE BICARBOXYLIC ACID-DERIVATIVES DISSOLVED IN NEMATIC LIQUID-CRYSTAL

The absorption spectra of some naphthalene derivatives of bicarboxylic acid dissolved in nematic liquid crystal mixture ZLI 1695 have been studied in detail using polarized light. On the basis of these spectra the order parameters S* and D* have been determined as a function of temperature. The experimental data have been presented as the plots of D* against S* in order to show the justification for the assumption of a temperature independent ratio of the potential parameter delta in the temperature range of measurements. Such an assumption has been made by using a relation D* = f (S*, delta) derived from the mean field theory for determination of S* and D*. The reduced absorption spectra for all the dyes investigated have been determined.