Erasable optical recording material for blue lasers

Abstract

An optical recording material for binary, multibit or volume data storage is described. The optical recording material comprises: (a) at least one dyestuff selected from polymeric azo dyestuffs and oligomeric azo dyestuffs, the dyestuff changing its spatial arrangement upon irradiation with polarized electromagnetic radiation; and (b) optionally at least one grouping having form anisotropy. The optical recording material has the following characteristics: (i) the absorption maximum of the dyestuff(s) is at least 30 nm less than 400 nm and/or 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) the 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) at 400 nm, under identical conditions, an optical writing operation performed upon the optical recording material proceeds no more slowly than at 500 nm, and birefringence values induced during the optical writing operation do not differ from those birefringence values induced at 500 nm by more than 10%.