Estimation of ground- and excited-state dipole moments of oxazine 1 in liquid and liquid crystalline media

The absorption and fluorescence spectra of a laser dye, oxazine-1 (OX1), in liquid and liquid crystalline media were studied at room temperature. The solvatochromic method was used to determine the ground- and excited-state dipole moments by means of Lippert–Mataga, Bakshiev, Kawski–Chamma–Viallet polarity functions. The solvent polarity has no large and regular effect on the spectral behavior of OX1, and thus it might be considered as a poor solvatochromic indicator dye. In addition, applicability of solvatochromic method for this dye in anisotropic media was investigated. On the other hand, nature and degree of the solute–solvent interactions were characterized using correlation of multi-parameter solvent polarity scales. Due to the theoretical restrictions and the dye molecular structure, deviations from the solvatochromic correlation were observed.

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► The ground and excited state dipole moments of oxazine 1 was determined.
► Applicability of solvatochromic method for anisotropic medium was investigated.
► Solute–solvent interactions were characterized using multi-parameter relationships.