| Abstract: | Copolymers of vinyl viologens such as N-vinylbenzyl-N′-yalkyl and N-(γ-methyacryloyloxy)propyl-N′-propyl-4,4′-bipyridinium dihalides and polar aprotic comonomers such as N-vinyl-2-pyrrolidone (VP) and N,N-dimethylacrylamide (DMA) were prepared by the copolymerizations of vinyl viologens with DMA and the chemical modifications of VP copolymers containing reactive halogens. Copolymers containing various viologen anions such as Br?, BF , SO , and I? were also prepared by the anion exchange of copolymers containing Cl?. The photocolor developments of these aprotic copolymers in the film state were completely reversible and faster than for the corresponding copolymers with protic comonomers such as acrylamide and 2-hydroxyethyl acrylate, all with characteristic absorption spectra attributable to single radical cations. |
