Solvent effects on the molecular resonance structures and photo-physical properties of a group of oxazine dyes

Absorption and fluorescence spectra of two oxazine dyes were recorded in various solvents in the range of 300-800 nm, at room temperature. The solvatochromic behavior of these substances and their solvent-solute interactions, both specific and non-specific, was analyzed using linear solvation energy relationship concept, suggested by Kamlet-Taft. The ground and excited state dipole moments of these substances and molecular resonance structures were also evaluated by a solvatochromic shift method.