Patent ID: 7691557

Claim:
A composition that cures by polymerization and that exhibits a substantially permanent color change during curing, comprised of: at least one polymerizable compound, the reaction of which is initiated by an active species selected from a first group, consisting of free radicals and ions; at least one initiator ingredient that generates said active initiating species when activated, said at least one initiator ingredient being present in an amount sufficient to effect substantially complete curing of said composition; and a non-photobleaching dye, present in said composition in an amount sufficient to impart perceptible color to said composition in the uncured state, the molecule of said dye comprising at least one conjugated system containing a chromophore that is subject to effective permanent decoupling, by reaction at at least one site, so as to cause substantially complete and substantially irreversible loss of said color, said composition containing at least one ingredient that produces a reactive alkylating species, that is effective for decoupling of said chromophore, in the presence of said active initiating species and under the conditions of polymerization of said composition.