On the explanation of the biphotonic processes in polyesters containing azobenzene moieties in the side chain

An explanation for the recently observed biphotonic transitions in side-chain polyesters with azobenzene moieties is given on the basis of experimental observations from optical and Fourier-Transform infrared absorption spectra. We present for the first time experimental evidence that a red laser beam at 633 nm causes cis-trans (Z—E) transitions in azobenzene.