Laser-induced luminescence (LIL) is the emission of light resulting from absorption of laser energy by a substance. Quantitative measurements show there is sometimes a very strong correlation between LIL and some physical characteristic of the material; many times this correlation is because fluorescence reveals relationships between molecular functional groups, such as conjugation. Because relationships between certain molecular functional groups are altered during degradation, LIL can be used to monitor these processes. Furthermore, these approaches can be adapted to a processing environment.
