Photosensitive elements based on polymeric matrices of diacetylenes and spiropyrans and the use thereof as coatings to prevent document reproduction
AssigneeBoard of Regents, The University of Texas System
InventorJean J. Robillard
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Abstract
Rapid changes in absorption are made within the volume of a photosensitive transparent member that absorbs incident radiation to prevent the photocopy of a document, the original transparency being restored after discontinuance of the incident radiation.
Claims29
A radiation sensitive material capable of being rendered substantially opaque to readout radiation when exposed to light of a document reproduction machine, said material comprising a dye sensitizer, and a polydiacetylene crosslinked with a spiropyran, wherein the spiropyran includes a benzopyran part, and wherein the polydiacetylene has the formula:
- C.ident.C-CH.sub.2 --O--R--O--CH.sub.2 --C.ident.C.sub.n,
- where R includes at least one benzene ring and n is an integer.
A process for preventing the reproduction of a document, comprising coating a document with a radiation sensitive material capable of being rendered substantially opaque to readout radiation when exposed to light of a document reproduction machine, said material comprising a dye sensitizer, and a polydiacetylene crosslinked with a spiropyran, wherein the spiropyran includes a benzopyran part, and wherein the polydiacetylene has the formula:
- C.ident.C--CH.sub.2 --O--R--O--CH.sub.2 --C.ident.C.sub.n,
- where R includes at least one benzene ring and n is an integer.
Dependencies are inferred from the claim text.