Impact of photosensitized oxidation and singlet oxygen on degradation of stabilized polymers

Photooxidation, an important component of polymer weathering, involves excited polymer-inherent chromophores and photoactive additives and impurities. Quenching of excited species by ground state molecular oxygen, the common component of air, results in the formation of singlet state molecular oxygen 1O2. This active form of oxygen is a strong oxygenation agent attacking stabilized polymers. Resulting transformations of the polymer matrix and additives have a negative effect on the service life of the material. The formation of 1O2, its properties, and reactions and products arising from stabilizers are outlined.