While doing some reading on sensitization of dichromate from an old book ("Light Sensive Systems - Chemistry and Applications of Nonsilver Halide Photographic Processes"), I came across something of interest with regard to what we were talking about earlier:
"...Oster and Oster (160, 161), investigated the photo-reduction of a variety of metal ions and found that this photoreduction can take place in the presence of photoreducible dyes. During exposure, the dye (Methylene Blue) is reduced to the leuco form, which serves as the reducing agent for the metal ion, thus being re-oxidized to the normal form; the source of the electrons is a chelating agent (ethylenedi-aminotetraacetic acid). By this method, dichromated-colloid layers are sensitised to the entire visible spectrum"
The references given (160, 161) are:
G. K. Oster and G. Oster. "J. Am Chem. Soc.", 81, 5543-45 (1959)
G. K. Oster and G. Oster. "Us Pat 3,074,794/1963
Sergio - interesting information
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Martin
Sergio - interesting information
Osters' papers (they can be found in SPIE's "Selected papers about holographic recording materials", MS 130) mark the beginning of most subsequent work on dye sensitized DCG (and many photopolymer systems).
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Sergio
Sergio - interesting information
Oster & Oster , where influent scientists in the polymer science, much of your work seed the basis of modern polymer science.
The described mechanism is the Jeff MB-TMG system described, I propose use Corcat P600 (Bayer)- water compatible or other to enhance the Jeff sytem, in the place of dichromate, others reductible ions may be used with MB(?)anyway may be worth with new amines donors because the pH MB control can be easily made. WDYT?
The described mechanism is the Jeff MB-TMG system described, I propose use Corcat P600 (Bayer)- water compatible or other to enhance the Jeff sytem, in the place of dichromate, others reductible ions may be used with MB(?)anyway may be worth with new amines donors because the pH MB control can be easily made. WDYT?
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Dinesh
Sergio - interesting information
"...anyway may be worth with new amines donors because the pH MB control can be easily made"
I think it may be worth pursuing this with regard to pH. Dark reaction is apparently severly restricted at a more basic pH, hence the addition of Ammonia. However, it also seems to increase the hardness and reduce the cross linking and so the modulation. If a material could be used to enhance the dichromate at a lower pH to restrict dark reaction and the same time keep the cross linking rate constant, It could maybe overcome a major obstacle to DCG.
I think it may be worth pursuing this with regard to pH. Dark reaction is apparently severly restricted at a more basic pH, hence the addition of Ammonia. However, it also seems to increase the hardness and reduce the cross linking and so the modulation. If a material could be used to enhance the dichromate at a lower pH to restrict dark reaction and the same time keep the cross linking rate constant, It could maybe overcome a major obstacle to DCG.