Rewritable optical recording material, for use with blue laser, contains polymeric azo dye giving optically induced birefringence

摘要

The absorption maximum of the dye differs by >= 30 nm. The optical density at 400 nm is /} 60% of that at the absorption maximum. The material is rewritable. Writing at 400 nm is no slower than at 500 nm. The difference in induced birefringence is /} 10%. Optical recording material for binary, multibit and/or volume data storage, contains polymeric and/or oligomeric azo dye, undergoing a change in spatial arrangement on irradiation with polarized electromagnetic radiation, optionally with shape anisotropic group. The absorption maximum of the dye differs by >= 30 (40-400) nm. The optical density at 400 nm is /} 60% of that at the absorption maximum. The material is rewritable by changing the state of polarization of the actinic light, such that the intensity is >= 80% of the original value after one erasure and rewrite cycle. Writing at 400 nm is no slower than at 500 nm, under otherwise the same conditions. The difference in induced birefringence is /} 10%. Independent claims are also included for the following: (a) memory containing the medium; and (b) the production of the memory by spin coating with the storage medium.