Patent ID: 6852766

Claim:
A method of multiphoton photosensitizing comprising (a) preparing a photoreactive composition comprising (1) at least one reactive species that is capable of undergoing an acid- or radical-initiated chemical reaction; and (2) at least one multiphoton photoinitiator system comprising photochemically effective amounts of (i) at least one multiphoton photosensitizer that is capable of simultaneously absorbing at least two photons and that has a two-photon absorption cross-section greater than that of fluorescein; (ii) optionally, at least one electron donor compound different from said multiphoton photosensitizer and capable of donating an electron to an electronic excited state of said photosensitizer; and (iii) at least one photoinitiator that is capable of being photosensitized by accepting an electron from an electronic excited state of said photosensitizer, resulting in the formation of at least one free radical and/or acid; and (b) irradiating said composition with light sufficient to cause simultaneous absorption of at least two photons, thereby inducing at least one acid- or radical-initiated chemical reaction where said composition is exposed to the light; with the proviso that said multiphoton photoinitiator system comprises at least one electron donor compound whenever said photoreactive composition comprises at least one said reactive species that is capable of undergoing an acid-initiated chemical reaction and that is either a curable species or a non-curable, reactive polymer.