Influence of temperature on the spectral-luminescent properties of rhodamine-dye solutions

This paper presents the results of studies of the influence of temperature on the spectral-luminescent characteristics of dilute solutions of 14 rhodamine dyes (unsubstituted rhodamine and its derivatives). The influence of temperature on the position and form of the absorption and flourescence spectra and on the absorptive power and luminescence yield of these solutions was investigated. The solvent used was ethanol, which vitrifies on freezing. To eliminate the influence of dye-molecule association on the optical characteristics measured, solutions of low concentration were used. The absorption and luminescence spectra at low temperature were studied using special cryostats. The temperature varied from 20 to -196C. The investigations show that even a slight change in molecular structure may lead to pronounced changes in the temperature dependences of their spectralluminescent properties.