A term used for changes in the luminescence parameters caused by changes in temperature, since the type of solvent and its temperature can effect the luminescence yield from an analyte as a result of quenching, exciplex formation, aggregation, etc.
Source:
PAC, 1984, 56, 231. 'Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy' on page 244 (https://doi.org/10.1351/pac198456020231)