use in the present invention include but are not limited to bisphenol a 1 2 3 triazoles such as 1 2 3 benzotriazole and 1 2 3 triazole ethyl 4 methyl 5 carboxylate octyl phydroxybenzoate and 4 hydroxycoumarin derivatives the third component of the leuco dye system is generally a polar solvent examples of polar solvents include but are not limited to lauryl alcohol cetyl alcohol and butyl stearate the polar solvent is an important component since it is the melting point of this component that controls the temperature at which the color change will take place these microencapsulated materials are typically colored at low temperatures below the melting point of the solvent and colorless at higher temperatures an example of a leuco dye system is one that generally contains the following components 1 leuco dye such as crystal violet lactone 2 weak acid such as 1 2 3 benzotriazole 3 solvent such as lauryl alcohol and optionally 4 salt such as myristylammonium oleate the salt dissociates at high temperature into amine and carboxylic acids and this dissociation raises the ph of the system and causes the dye to take up its colorless closed ring form in the microencapsulated state these leuco dye systems are the preferred embodiment for use in this invention the present invention will be described in greater detail with reference to the following example all formulations listed in the.