Structure-Optical Behavior Relationships of Epoxy-Based Polymers Having Azobenzene Units

FERNÁNDEZ R.; RAMOS J.; GALANTE M.J; OYANGUREN P.A.; MONDRAGON I

Roma, Italia

Simposio; Nanofun-Poly 2008, 4th International Symposium on Nanostructured and functional polymer-based materials and Nanocomposites; 2008

Recently, there has been a growing focus on the study and application of photo-responsive polymers containing azobenzene moieties because of their promising and diversified applicability in optical data storage, optical switching and optoelectronics [1-11]. The generation of optical anisotropy induced by the excitation of azobenzenes incorporated in polymer matrices with linearly polarized light takes place as the result of repeated photo-isomerization processes. In this context, in previous studies, we reported the synthesis and characterization of different epoxy-based copolymers prepared with the same azobenzene monomer [12]. The optical behaviour of azo-modified polymers depends on the environment in which azobenzene moieties exist. In this work, thermoplastic and thermoset copolymers containing azobenzene groups are compared using optically induced birefringence on spin-coated films. We evaluate structural parameters of the polymer matrix in the time to achieve birefringence, as well as the time to randomize the orientation. We relate glass transition (Tg) and mobility in polymer systems with the molecular reorientation showing the benefits of polymer networks in the stability of the remaining birefringence. We measure the effects of varying azobenzene group concentration and, finally, we also present results of absorbance measurements.