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.