Writable and erasable high-density optical storage media

The invention relates to an optical storage medium comprising a substrate and a storage layer, wherein the storage layer comprises a compound of the formula (I) or (II)in which A and A', independently of one another, are unsubstituted or mono- or di-halo-, -hydroxy-, -C1-C6alkyl-, -C1-C6alkoxy-, -cyano- or -nitro-substituted phenyl, pyridyl, pyrrolyl, imidazolyl, furyl or thienyl, which can, if desired, be fused to a benzene ring, are halide, tetrafluoroborate or unsubstituted or with one or more halogen substituted C1-C6alkane-sulfonate, benzenesulfonate, C1-C6alkylbenzenesulfonate, C1-C6alkylsulfate or di-C1-C6alkyl-phosphonate of N-C1-C6alkyl-pyridiniumyl, or are unsubstituted or mono- or di-hydroxy-substituted C2-C6alkyl or C2-C6alkenyl, whose chain may be uninterrupted or interrupted by one or two oxygen atoms, B and B', independently of one another, are 2 H, S, S2 or SO2, and n and n', independently of one another, are each a number from 1 to 4. The invention also relates to a process for the optical writing, storage, reading, modification or erasing of data at a wavelength of from 400 to 700 nm using a novel recording medium, to an optical recorder for the optical writing, modification or erasing of data using only continuous laser radiation or only modulated laser radiation, to a process for converting a compound of the formula (I) or (II) from a black form into a red form by mechanical force, and to new compounds of the formula (I) or (II).