Abstract: A composition which comprises a light absorbing layer adhered to an underlying layer containing a photo-chromic colorant, which photo-chromic colorant has been activated by exposure to UV light to undergo a reversible color change, and wherein the rate of color reversion is dependent on temperature, is provided. The ultraviolet light and/or visible light absorbing layer may also contain components which reflect rather than absorb light and can be conveniently applied via thermal transfer or ink jet to a substrate comprising the photo-chromic colorant to protect it from unwanted exposure to UV and/or certain wavelengths visible light. The composition is conveniently employed in a temperature time indicator (TTI).

Abstract: Described are coating compositions for marking substrates comprising a) a solvent, b) a salt of a phosphorus or boron containing acid and an amine or imine, c) a salt of a non-phosphorus and non-boron containing acid and an amine or imine, d) a binder, and e) optionally additional ingredients, their manufacture and use, wherein the above-mentioned salts can also be present in an encapsulated form as a kind of pseudo-pigment. Substrates coated by the above compositions can be marked by laser irradiation.

Abstract: A composition which comprises a light absorbing layer adhered to an underlying layer containing a photo-chromic colorant, which photo-chromic colorant has been activated by exposure to UV light to undergo a reversible color change, and wherein the rate of color reversion is dependent on temperature, is provided. The ultraviolet light and/or visible light absorbing layer may also contain components which reflect rather than absorb light and can be conveniently applied via thermal transfer or ink jet to a substrate comprising the photo-chromic colorant to protect it from unwanted exposure to UV and/or certain wavelengths visible light. The composition is conveniently employed in a temperature time indicator (TTI).