ABSTRACT
Peroxycyclohexadienones absorb solar UV radiation in the range of 300-380 nm (60). The photolysis of the peroxidic bond is assisted by n-n* excitation of the conjugated cyclohexadienonyl system and yields, under conditions of polymer weathering, derivatives of cyclopentadiene or cyclopentene, such as 104 or 105. Photolysis of 91, 93, 97, or 98 has a prooxidative effect in the initial stages of photooxidation of hydrocarbons or high-impact polystyrene. The photolytic product 104 has a pronounced light-screening effect, if present at relatively high concentration levels (about 0.10/0) (49).
