MECHANISMS OF RELEASE OF ENERGY ABSORBED BY DYES.

Ultraviolet and visible energy absorbed by organic molecules always raises them to a higher electronic energy level. In most cases, the excess electronic energy is rapidly transformed to heat, by successive nonradiative transitions which produce increased molecular motion. Possible effects of the case of energy not sufficiently rapidly degraded to molecular energy are described, with examples, to illustrate some of the physical phenomena underlying the interrelationships between fluorescence, susceptibility to fading, and related electronic processes.