New photosensitive materials based on triazene derivatives

Triazene derivatives are studied as potential doping systems in polymeric films for direct laser wiring (DLW) of volume phase hologram. In particular, aryltriazenes can undergo to the group cleavage with the formation of volatile nitrogen and two radicals when irradiated with UV/violet light. Three derivatives, bearing different substituents, are characterized in n-hexane solution with UV-vis spectroscopy and the different photo-reactivity is highlighted. The best candidate, with a nitro group on the phenyl ring, is then added to a polyurethane matrix at 10% wt and the photoreactivity is evaluated together with the phase modulation in thin films deposited on Si wafers. A 5% change in the product of thickness and refractive index is measured by means of spectral reflectance. Simple patterns are transferred to the films using a DLW facility equipped with a 405 nm laser and studied with the phase contrast microscope.