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Abstract: The synthesis and photochemical reaction mechanism of N-benzoyl oxazine derivatives have been investigated. The synthesized materials were found to be photosensitive and capable of generating oxazine dye upon light irradiation. The initial reactions were found to include homolytic bond cleavage between the oxazine nitrogen and benzoyl carbon atoms proceeding through the excited singlet state and the formation of oxazine and benzoyl radicals. Subsequent reaction steps include direct electron transfer between two oxazine radicals or disproportionation of the oxazine dimer species formed through the recombination of two oxazine radicals. These reactions lead to the formation of the oxazine dye cation and anion pair. [Copyright &y& Elsevier]

We describe briefly, the mechanism and characteristics of a versatile new photochromic molecule that is capable of performing as a medium for non-destructible high capacity readout molecular storage devices. This molecular memory consists of two different molecular components, chemically bonded together. It retains the photochromic and spectroscopic properties of each individual molecular component and the changes in the property of one component influence the fluorescence quantum yield of the other. The write form is a polar closed structure molecule that does not fluoresce. When transformed into the read form it exhibits an open structure, is non-polar and allows for intense fluorescence. The read form excited state is located at 660 nm, which is at lower energy than the excited state of the write form, therefore no erasing occurs while reading. Erasing is achieved by excitation at 400 nm, which is higher than 530 nm write energy. The write/read/erase spectra and mechanism have been measured in solution and in solid polymer, including PMMA matrices. [Copyright &y& Elsevier]

Describes the methods and systems used for storing and accessing information in three dimensions by means of two-photon absorption. Two-photon processes; Storing and accessing information in three-dimensional systems; Photochromic materials for 3-D memory; Organic dye Read-only-memory (ROM) material; 3-D memory system characteristics; Conclusions.