Solvent Effects in Room Temperature Phosphorescence

Room temperature phosphorescence (R TP) analysis is a technique in which solutions containing organic phosphors are applied to filter paper and dried in the absence of oxygen. Adsorption to the paper inhibits molecular vibrations and promotes phosphorescence. Although the solvent must be removed by volatilization before phosphorescence can occur, it appears that the nature of the solvent affects the intensity of the resulting phosphorescence. We examined the room temperature phosphorescence of p-aminobenzoic acid which had been dissolved in water, organic solvents, or mixtures of water and organic solvents. It was found that solvent volatility had little correlation with RTP intensity and that solvents with high dielectric constants produced more intense signals