Method of recording data in an optical data storage medium and an optical data storage medium

A method for recording holographic data in an optical data storage medium, said method comprising:

• (i) providing an optical data storage medium comprising:
• (a) a thermoplastic polymer matrix, (b) a latent acid generator, (c) a sequential two-photon non-linear sensitizer, and (d) a reactant comprising a protected benzophenone;
• (ii) irradiating a volume element of the optical data storage medium with an interference pattern to cause sequential two-photon absorption by the non-linear sensitizer;
• (iii) an upper triplet energy transfer from the non-linear sensitizer to the latent acid generator, thereby generating an acid,
• said interference pattern comprising an incident radiation having a wavelength and an intensity sufficient to cause the upper triplet energy transfer, wherein the latent acid generator is substantially non-responsive to said incident radiation;
• (iv) reacting a plurality of protected benzophenones with the acid generated to form a plurality of hydroxy benzophenones, thereby causing a refractive index change within the volume element;
• and
• (v) producing within the irradiated volume element refractive index variations corresponding to the interference pattern, thereby producing an optically readable datum.

An optical data storage medium, comprising:

• (a) a thermoplastic polymer matrix;
• (b) a sequential two-photon non-linear sensitizer capable of absorbing incident radiation having a wavelength and an intensity sufficient to cause sequential two-photon absorption by the non-linear sensitizer;
• (b) a latent acid generator capable of generating an acid upon upper triplet energy transfer from the non-linear sensitizer, and being substantially non-responsive to said incident radiation;
• (d) a reactant comprising a latent chromophore,
• wherein at least one latent chromophore is capable of forming at least one chromophore by reacting with the acid generated, thereby causing a refractive index change in the optical data storage medium.