Novel photochromic polymer films containing ion-pair charge-transfer complexes of 4,4′-bipyridinium ions for optical recording

Abstract

Elastic polymer films containing 4,4′-bipyridinium salts with tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as part of the main chain showed persistent and reversible colour changes due to photoinduced electron transfer upon excitation of an ion-pair charge-transfer band (λ_ex >365 nm)in vacuo with the lifetime of the coloured state markedly dependent on temperature.