Solvent effects on the absorption and emission spectra of some nematic liquid crystals: Determination of dipole moment and first-order hyperpolarizability

The effect of solvent on the absorption and fluorescence spectra of two liquid crystalline molecules LC1 and LC2 were studied. These data were used to evaluate the values of the change in the dipole moment between the ground and excited state and the first-order hyperpolarizability "β" in each solvent. The values of β gives an indication of how these liquid crystalline samples can find applications as nonlinear materials. The β values are in the range 1-1.9 × 1029 esu for LC1 and LC2. The values of β indicate that these compounds can be used as good nonlinear materials. Here solvatochromism has been used as an effective tool to estimate the hyperpolarizability in solution.