Time-temperature indicating device

A time-temperature indicator device comprising (i) at least one active reactant being at least a part of an electrical component, wherein said electrical component comprises an electrically conductive material, said at least one active reactant is selected such that it intrinsically changes at least an electrical property of said at least a part of said electrical component at a rate that is temperature dependent, said at least one active reactant is selected such that it intrinsically changes at least an electrical property of said at least a part of said electrical component at a rate that is temperature dependent, wherein the active reactant is a metal or an oxide thereof, or a semiconductor;

• (ii) at least one first passive reactant in the form of a viscous substance;
• and (iii) at least one second passive reactant, wherein said at least one first passive reactant is located between said at least one active reactant and said at least one second passive reactant, wherein said at least one second passive reactant is a viscous substance wherein said chemical and/or physical reaction is a reaction between said at least one active reactant and said at least one second passive reactant and wherein said at least one first passive reactant is selected such that it causes time dependent transfer of heat towards said at least one second passive reactant thereby causing time-temperature dependent development of said chemical and/or physical reaction.

A method of time temperature indication comprising performing a chemical and/or physical reaction between at least one active reactant and at least one passive reactant effecting a change in at least an electrical property of an electrical component wherein said at least one active reactant is at least a part of an electrical component, wherein said electrical component comprises an electrically conductive material, wherein the active reactant is a metal or an oxide thereof, or a semiconductor, and wherein said at least one passive reactant is a viscous substance;

• wherein said viscous substance is in contact with said active reactant, such that said performing said chemical and/or physical reaction comprising reacting said at least one active reactant with said at least one passive reactant to induce temperature dependent or time-temperature dependent disintegration of said active reactant, wherein said at least one passive reactant and said active reactant are selected such that they cause temperature dependent or time-temperature dependent development of said temperature dependent or time-temperature dependent disintegration, thereby effecting a change in at least an electrical property of said at least a part of an electrical component at a rate that is temperature dependent or time-temperature dependent;
• wherein said change in at least an electrical property of said at least a part of an electrical component is associated with a change in a visual physical property of the indicator device.