The Influence of Anisotropic Polymeric Solids on Dopant Orientation and Reactivity: Azobenzene in Low Density Polyethylene

Abstract The conformational studies of the title compound, both trans and photogenerated cis form, were carried out in oriented polyethylene (PE) by linear dichroism (LD) method in UV/Vis and IR region. The observed orientation factors for the vibrational and electronic transition moment direction are consistent with the assumption of a rigid planar structure for trans form, whereas cis form attain globular conformation with the phenyl rings twisted perpendicular to the -N=N- plane. The trans-cis photoisomerization is also measured in polarized light with electric vector parallel and perpendicular to the uniaxially stretched polyethylene sample. Although the macroscopic stretching of the PE film altered the distribution of the site size the rate of phototransformation is faster in the stretched than in unstretched sample.