PHOTOPHYSICS OF POLYMERS

The first step, of course, is the absorption of electromagnetic energy, transforming it into excited molecular states. 

In situations where bimolecular encounters dominate, typical for polymers, such encounters may lead to an electronic relaxation of the system, termed quenching. In general, such collisions may be written 

The possible bimolecular quenching process includes (41) (a) chemical reaction, (b) enhancement of nonradiative decay, (c) electronic energy transfer, or (d) complex formation. 

Chemical reactions involve cross-linking, degradation, and rearrangement. Electronic energy transfer involves exothermic processes, where part of the energy is absorbed as heat, and part is emitted via fluorescence or phosphorescence from the donor molecule. 

Features of excimer fluorescence important in polymer characterization include intensity of radiation, intensity changes, decay rates, extent of frequency shifting of the fluorescence, and depolarization effects. 

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CSP Sung. In CE Hoyle, JM Torkelson, eds. Photophysics of Polymers. ACS Symposium Series 358, Washington, DC American Chemical Society, 1987, p 463. 

Photochemistry and Photophysics of Polymers, eds., N. S. Allen and W. Schnabel, Applied Science, Ltd., London (1984). 

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