Solvent polarizability and anisotropy effects on the photophysical behavior of oxazine 1: an appropriate polarizability indicator dye.

The spectroscopic features of a laser dye, oxazine 1 (OX1), were investigated in liquid and in liquid crystalline solutions as a function of the solvent polarity and polarizability. The nature of spectral shift was investigated by studying the absorption spectra of the dye in different solvents. The spectral shifts were correlated by the solvent polarity and polarizability. As a result, the solvent polarity has no large and regular effect on the spectral behavior of the dye, and thus it might be considered as a poor solvatochromic dye. In contrast, an excellent linear correlation was observed between the solvent polarizability and the spectral properties of the dye, and therefore, this dye might be considered as a good indicator for measuring the solvent polarizability. The absorption and fluorescence spectra of the dye were investigated in nematic solvents with high birefringence. In nematic solvents, anisotropy of polarizability has a major contribution to the shaping of the absorbance and emission spectra of OX1.