Effects of temperature above ambient (300–550°K) on liquid scintillators are presented. Under excitation by high energy or light usually a reduction in fluorescence with high temperatures is found. However, when excimers are present, a rise may be found. The energy transfer as a function of temperature is studied by means of a theoretical formula, and is found to be greatly temperature dependent. Its dependence is found to be directly associated with variation in fluorescence properties of the solvent by itself.