title: Origin of the photo-cross-linking process in dichromated polyacrylamide under conventional and laser irradiation.
abstract: This work is devoted to determining the contribution of amide groups in the photoredox and cross-linking process of dichromated polyacrylamide based on the fate of the photoactive species and of the polymer under conventional and laser irradiation. It was shown that, in parallel to the reduction of chromium(VI) into chromium(V), the cross-linking of the matrix occurred through a complexation reaction around chromium(V) and through formation of covalent bonds between macromolecular chains. A comparison with dichromated poly(vinyl alcohol) was also reported to highlight the role of the chemical structure of the polymeric matrix in the mechanism of hologram formation. Moreover, for the first time it was demonstrated by in situ infrared spectroscopy that the physicochemical modifications undergone by the photosensitive materials were similar for the two modes of irradiation.
authors.affiliation: Laboratoire de Photochimie Moléculaire et Macromoléculaire, Unité Mixte de Recherche Université Blaise Pascal/Centre National de la Recherche Scientifique 6505, 24 avenue des Landais, F-63177 Aubière, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Berger
authors.forename: Lawrence
authors.initials: L
authors.lastname: Frezet
authors.forename: Yaël
authors.initials: Y
authors.lastname: Israëli