Patent ID: 7022460

Claim:
An optical recording material for at least one of binary, multibit and volume data storage, comprising: (a) at least one dyestuff selected from polymeric azo dyestuffs, said dyestuff changing its spatial arrangement upon irradiation with polarized electromagnetic radiation; and (b) optionally at least one grouping having form anisotropy, wherein, (i) the absorption maximum of the dyestuff is at least one of, at least 30 nm less than 400 nm and at least 30 nm greater than 400 nm, (ii) at 400 nm the dyestuff reaches an optical density of not more than 60% of its absorption maximum, (iii) said optical recording material has the capacity for being rewritten on by changing the state of polarization of actinic light, an intensity of at least 80% of the original value being achieved after a deletion/rewriting cycle, and (iv) wherein at 400 nm, under identical conditions, an optical writing operation upon said optical recording material proceeds no more slowly than at 500 nm, and birefringence values induced during said optical writing operation do not differ from those birefringence values induced at 500 nm by more than 10%, further wherein said polymeric azo dyestuff is a polymer represented by the following formula XIV, p being between 10 and 1,000.