Dichromated Poly Research Articles

Why does poly(acrylic acid) addition improve the quality of holograms recorded in dichromated poly(vinyl alcohol)?

Holographic measurements have shown that the addition of 0.5% of poly(acrylic acid) (PAA) can improve the quality of holograms recorded in poly(vinyl alcohol) (PVA) doped with ammonium dichromate (ADC). The purpose of this paper is to explain this improvement. First, an analytical approach investigated the structural and architectural modification of the polymeric matrix and the fate of the various chromium species within PVA/PAA/ADC films. The addition of PAA in dichromated PVA led to a pre-reticulation of the polymeric matrix. This process increased with the amount of PAA. Second, an analytical approach focused on the evolution of PVA/PAA/ADC films upon irradiation at 365 nm, which is representative of hologram formation. The improvement brought by the presence of 0.5% of PAA in PVA/ADC was assigned to an additional source of crosslinking through the formation of covalent bonds. This process paralleled the crosslinking through coordination bonds involving Cr(V) and PVA units. At 0.5% of PAA, the mobility of the medium before exposure was sufficient to allow the migration of the species involved in the reticulation process during hologram formation, whereas higher concentrations of PAA inhibited this migration.

Photocrosslinking in dichromated poly(acrylic acid) during hologram recording and comparison with dichromated poly(vinyl alcohol)

AbstractPhototransformations involved in dichromated poly(acrylic acid) (DCPAA) were analyzed under irradiation conditions representative of hologram formation. It was shown that, in parallel to the reduction of chromium(VI) into chromium(III), the crosslinking of the matrix occurred through formation of covalent bonds between macromolecular chains. A comparison with dichromated poly(vinyl alcohol) (DCPVA) irradiated under the same conditions was also reported giving evidence for the crucial role played by the chemical structure of the polymeric matrix in the hologram formation. The combined approach based on the fate of both the absorbing species, chromium(VI) and the polymer allowed to completely elucidate the reactions taking place upon irradiation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 636–642, 2008

New combined polymer/chromium approach for investigating the phototransformations involved in hologram formation in dichromated poly(vinyl alcohol)

AbstractThe photochemical behavior of dichromated poly(vinyl alcohol) films has been analyzed upon exposure at 365 nm in relationship with the performances of holograms recorded in such photosensitive materials. The evolution of both involved species, poly(vinyl alcohol) and chromium, has been quantified by the implementation of an innovative approach. This approach combines the monitoring of the structural modification of the polymeric matrix and the fate of the various chromium species. For the first time, it has been established that chromium(V) not only is an indicator of the hologram quality, as previously assessed, but also appears to be responsible for the crosslinking implied in the hologram formation. Actually, the crosslinking has been proved to proceed through coordination bonds around chromium(V), which acts as a bridge between the polymeric chains. The role played by the ammonium cations in the hologram quality has also been elucidated. The improvement brought by ammonium dichromate with respect to potassium dichromate involves amide groups resulting from poly(vinyl alcohol) phototransformation. These groups provide additional chelating sites for chromium(V), leading to an increase in the matrix crosslinking. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1317–1325, 2006

Polyaniline-poly(vinyl alcohol) composite as an optical recording material

Conducting polymer image and diffraction grating pattern were recorded in dichromated poly(vinyl alcohol) (DCPVA) films by visible light exposure, in a process resembling photolithography. Aniline, used as a chemical developer, polymerized into the unexposed areas of the DCPVA matrix, yielding a composite material which allowed permanent optical information storage and exhibited optical properties characteristic of polyaniline. The photoreduction properties of the DCPVA films and the optical properties of the composite were studied by UV–VIS spectroscopy. The characterization of the diffraction grating composite gave a line width of 12.15 μm and a diffraction efficiency of 32%.

Polyaniline-Poly(Vinyl Alcohol) Composite: Spectroscopic Characterization and Diffraction Grating Recording

Diffraction gratings were recorded both optically and interferometrically in dichromated poly(vinyl alcohol) (DCPVA) films by means of dichromate photoreduction. Aniline was used as a chemical developer, through in situ polymerization in the unreduced parts of the film. The resulting composite material shows the optical and chemical properties of polyaniline and the mechanical resistance of PVA. Characterization of the gratings gave a line width of 12.2 µm and a diffraction efficiency of 32%. Uv-vis spectroscopy was used to study dichromate photoreduction and the optical properties of the composite..

Polyaniline-Poly(Vinyl Alcohol) Composite: Spectroscopic Characterization and Diffraction Grating Recording

Diffraction gratings were recorded both optically and interferometrically in dichromated poly(vinyl alcohol) (DCPVA) films by means of dichromate photoreduction. Aniline was used as a chemical developer, through in situ polymerization in the unreduced parts of the film. The resulting composite material shows the optical and chemical properties of polyaniline and the mechanical resistance of PVA. Characterization of the gratings gave a line width of 12.2 μm and a diffraction efficiency of 32 %. Uv-vis spectroscopy was used to study dichromate photoreduction and the optical properties of the composite..

Dark self-enhancement in dichromated poly(vinyl alcohol) gratings: a detailed study

Experimental results concerning the real-time hologram recording process in dichromated poly(vinyl alcohol) are presented. Self-enhancement, the increase in diffraction efficiency of the holographic gratings in the dark after recording, is also presented. The influence of the recording parameters (pH, exposure energy, dichromate concentration) on the self-enhancement gain is shown. Maximum gain was 6, and self-enhancement occurred during the 3 days following the exposure. The results and a model for the reduction of chromium ions corresponding to the formation of the grating are discussed.

Charge-transfer phenomena in holographic recording material: dichromated poly(acrylic acid)

Charge-transfer phenomena in holographic recording material: dichromated poly(acrylic acid)

Xanthene dye sensitized dichromated poly(vinyl alcohol) recording materials: holographic characterization and ESR spectroscopic study

Dichromated poly(vinyl alcohol)-xanthene dye (DCPVA-XD) systems have been employed as real-time holographic recording materials. Holographic performance of the undeveloped and developed dichromated poly(vinyl alcohol) (DCPVA) films with three different xanthene dyes (XD) namely fluorescein (Fl), eosin Y (EY) and rose bengal (RB) are evaluated through diffraction efficiency profiles. In addition, a systematic electron spin resonance (ESR) spectroscopic investigation was also performed on these systems to study the mechanism of holographic recording and observe the influence of XD in the photoprocesses. The photochemical evolution of Cr v, Cr III, polymer radical and dye radical in these systems has been monitored and a suitable xanthene dye photosensitized mechanism is proposed.

Metal ion doped polymers as media for optical memories

AbstractPolymer materials are making an impact on optical storage technology to develop high information density and fast access type memories with a high read‐out efficiency. The principle and advantages of three‐dimensional (3‐D) data storage in the form of interference patterns (holograms) have been outlined. Three different information storage materials have been developed by doping metal ions such as Cr(VI) and Fe(III) in water‐soluble polymers, namely poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA), which need no further thermal or chemical treatment. Volume transmission holograms have been recorded in dichromated poly(vinyl alcohol) (DCPVA), ferric chloride doped poly(vinyl alcohol) (FePVA) and dichromated poly(acrylic acid) (DCPAA), with and without an electron donor (dimethyl formamide), and xanthene dyes (fluorescein, eosin Y and Rose Bengal). Different parameters influencing the holographic performance have been optimized to achieve a high real‐time diffraction efficiency (∼70%). An electron transfer process from the polymer matrix to Cr(VI)/Fe(III), leading to the photocrosslinking of the polymer in the form of an interference pattern, has been suggested as the mechanism of information storage (hologram recording) in these materials.

Polymer waveguides: characterization through prism–film coupler method

Cr(VI) and Fe(III) doped polyvinyl alcohol) and poly(acrylic acid) polymers have been used as real-time holographic recording media as well as materials to fabricate planar waveguides. Planar wave guides were made of these metal ion doped polymer thin films. Changes in the absorption spectra of these polymer films due to irradiation with an intense illumination of 468 nm light were observed. Modifications in optical properties of dichromated poly(vinyl alcohol) (DCPVA), dichromated poly(acrylic acid) (DCPAA), and ferric chloride doped polyvinyl alcohol) (FePVA) were experimentally determined by the prism–film coupler (PFC) method for the first time. Changes in the refractive index at 632.8 nm were monitored for different exposure energies. Modification of the modal properties was observed and the refractive index of these films was also determined from the angular position of the guided modes. Optical losses in both exposed and unexposed films of DCPVA, DCPAA, and FePVA were measured employing a coupling set-up with two prisms. Observed results suggest that these materials can find successful applications in promising areas like integrated optics and planar optical interconnects.

Primary photoprocesses of chromium(VI) in real-time holographic recording material: dichromated poly(vinyl alcohol)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrimary photoprocesses of chromium(VI) in real-time holographic recording material: dichromated poly(vinyl alcohol)Gurusamy Manivannan, Rupak Changkakoti, Roger A. Lessard, Gilles Mailhot, and Michele BolteCite this: J. Phys. Chem. 1993, 97, 28, 7228–7233Publication Date (Print):July 1, 1993Publication History Published online1 May 2002Published inissue 1 July 1993https://doi.org/10.1021/j100130a017RIGHTS & PERMISSIONSArticle Views143Altmetric-Citations44LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (741 KB) Get e-Alerts

Cr(VI)- and Fe(III)-doped polymer systems as real-time holographic recording materials

Volume transmission holograms have been recorded in dichromated poly(vinyl alcohol) (DCPVA), dichromated poly(acrylic acid) (DCPAA), and ferric chloride poly(vinyl alcohol) (FePVA) films using a 488-nm light (from an argon-ion laser), and the hologram development has been monitored in real time using a 647-nm line of the krypton laser. The influence of different chemical parameters (e.g., pH and electron donor) on the holographic efficiency has been determined, and an efficiency value as high as 70% was achieved in all three recording media. Further, the possible primary photoprocesses responsible for the hologram formation are tentatively identified and discussed