Thermoluminescence is phosphorescence triggered by temperatures above a certain threshold. This should not be confused with incandescence, which occurs at higher temperatures.
In thermoluminescence, heat is not the primary source of the energy, only the trigger for the release of energy that originally came from another source. It may be that all phosphorescences have a minimum temperature, but many have a minimum triggering temperature below normal temperatures and are not normally thought of as thermoluminescences.
