Functional monomers and polymers. XCVI. Photochemical reactions on oligo‐ and polyethyleneimines which contain pendant thymine bases

Abstract
The photodimerization reaction of oligo‐ and polyethyleneimine derivatives which contain pendant thymine bases in various amounts was studied in aqueous solution in a wide pH range and in N, N‐dimethylformamide solution. The photodimerization reaction of these derivatives in poly(methyl methacrylate) was also studied. It was found that its quantum efficiency tended to increase as thymine units were added to the oligomers and copolymers. This result is discussed in terms of the effect of the nearest neighboring thymine units and singlet energy migration, particularly in the polymers.