| Abstract
| - A novel polyaniline containing azo groups has been synthesizedusing horseradishperoxidase catalyzed oxidative free radical coupling of4,4‘-diaminoazobenzene in the presenceof hydrogen peroxide. The spectral changes observed indicatepolymerization accompaniedby trans−cis isomerization, leading to structural constraints in thegrowing polymer chain.This soluble azo polymer consists of azo groups in the main chainas well as in the sidechain. Upon photoexcitation of the polymer in solution, thechromophores undergo structuralphotoisomerization. The polymer relaxes to a conformation havingspectral features identicalto those of the conformation prior to photoexcitation if the excitationis carried out withinthe trans absorption band. Photoexcitation at the cis absorptionband or thermal kineticrandomization of the chromophore conformation in the polymer insolution results inrelaxation of the structural constraints, which leads to a differentconstrained conformation.
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