Influence of Temperature and Ethanol Content on Aggregation of Rhodamine 6g Molecules in Aqueous Ethanol Solutions

The effect of temperature on absorption spectra of Rhodamine 6G at concentrations of 10 and 10 M in water:ethanol solutions of various ethanol content was studied. The dimeric molecular fraction of Rhodamine 6G (10 M) was found as a function of temperature and ethanol content in the aqueous solution. It was shown that the absorption spectrum of Rhodamine 6G dimers (10 M) is dependent on temperature and ethanol content in the aqueous solution. Based on the relationship between Jand H-bands in the absorption spectrum of Rhodamine 6G dimers, both the angle between planes of associated Rhodamine 6G dye molecules and the free enthalpy of association were calculated. The structure of Rhodamine 6G dimers depends essentially on the ethanol content and aqueous ethanol solution temperature while experiencing the most temperature changes at an ethanol concentration of 25%.