radiation source is removed.

In a general sense, there is no distinct boundary between the emission times of fluorescence and phosphorescence (i.e. if a substance glows under a black light it is generally considered fluorescent, and if it glows in the dark it is often simply called phosphorescent). In a modern, scientific sense, the phenomena can usually be classified by the three different mechanisms that produce the light and the typical timescales at which they emit light: fluorescence, triplet