Dominant factors of preventing Rhodamine 6G from dimer formation in aqueous solutions

Rhodamine 6G/water/alcohol or carboxylic acid systems were studied. Rhodamine 6G molecules, which tend to associate into nonfluorescent dimers in aqueous solution, were prevented from dimerization by mixing them with organic compounds. It was found that additives with smaller dielectric constants prevented the dye molecules from associating to effectively form dimers. It was found that 2-butanol and isobutyric acid were the most effective additives for dissolving Rhodamine 6G dimer and that the amount demanded to obtain the necessary concentration of monomer in aqueous solution was less than 10%.