Long term rapid color changing time indicator

A time indicator comprising:

• a front part comprising an opaque layer, a colorant layer in contact with the opaque layer at an interface, a neutralizing layer in contact with the colorant layer at a surface of the colorant layer opposite the interface, and a transparent layer in contact with the opaque layer at a surface of the opaque layer opposite the interface, wherein the colorant layer comprises a matrix and a colorant in the matrix, the colorant has a non-migratory form in which the colorant does not migrate in the matrix to the interface and a migratory form in which the colorant migrates in the matrix to the interface;
• and
• a back part comprising a reactant capable of migrating in the colorant layer and the neutralizing layer,
• wherein, when the front part and the back part are placed in contact, the reactant migrates into the neutralizing layer and an amount of the reactant reacts with an amount of a coreactant in the neutralizing layer to form a reaction product such that at least a portion of the reactant entering the neutralizing layer does not migrate out of the neutralizing layer, and
• wherein unreacted reactant migrates into the colorant layer and reacts with the non-migratory form of the colorant converting the non-migratory form of the colorant to the migratory form of the colorant such that the migratory form of the colorant migrates to the interface and through the opaque layer to cause a visual color indication in the transparent layer.