| abstract |
The invention relates to an optical recording medium comprising a substrate, a reflecting layer and a recording layer, wherein the recording layer comprises a compound of formula (I),(II),(III); wherein R 1 , to R 13 , may be hydrogen or a variety of substituents, but R 1 , and R 11 are not simultaneously hydrogen;Y m − is an inorganic, organic or organometallic anion, or a mixture thereof; Z n+ is a proton or a metal, ammonium or phosphonium cation, or a mixture thereof; m, n and o are each independently of the others an integer from 1 to 3; and p and q are each a number from 0 to 4, the ratio of o, p and q to one another, depending on the charge of the associated sub-structures, being such that there is no excess positive or negative charge in formula (I), (II) or (III). Also claimed are the use of a xanthene perchlorate in the preparation of compounds of formula (I), (II) or (III) having organometallic anions, and the use of lactates in the application of layers of dye to grooved substrates by spin-coating. |