Investigation of the primary photochemical process in chromium doped polymeric material: Interactivity with holography

摘要

A comparative investigation of the photochemical behavior of dichromated gelatin (DCG), dichromated polyacrylic acid (DCPAA) and dichromated polyvinylalcohol (DCPVA) gives evidence for the similarity of the photochemical behaviour involved when recording holograms in DCG and DCPVA. Chromium (V), the chromium species resulting from the photoredox process between the starting chromium (VI) (dichromate) and the polymeric chain, is stable, likely strongly complexed in gelatin and polyvinylalcohol. The quantum yields of the reaction are high and similar for both reactions. On the contrary, even though chromium (V) is also formed during the primary process in DCPAA, this species is quite unstable and disappears as soon as tge irradiation is stopped. The behavior observed in DCG can be assigned to the presence of CH groups on the polymeric chain, these groups being the only groups present in polyvinylalcohol.