Heat-induced color changes

In contrast to the color changes that occurred in modern, uncoated silk after exposure to heat, the light-induced color change was not indicative of the tensile properties of the fabric. Loss in tensile properties with irradiation continued while the color remained static. 

Fig. 6 Optical effects in dynamers. Color change and fluorescence generation induced by component recombination at the interface between two dynameric films. (Top) Schematic representation of the process yielding two new combinations at the interface of two superimposed films of dynamers. (Bottom) Photographs of an actual experiment, before (left) and after (center and right) recombination induced by heating...

In the initial prosecution, the examiner indicated that the compounds were not patentable over known materials. According to Dr. Dessauer, The examiner told us that similar imidazoles had been reported to give off light when heated, and what we had showed no novelty over the prior art. I replied that the phenomenon that we had invented was photochromism, a color change induced by light, as in certain organisms like salamanders, while what he cited... 

Mechanistic details of this reaction are scarce, but Aratani (14) mentions that the catalyst needs to be activated by heating in the presence of the diazo compound at 75-80°C until nitrogen evolution is observed and the color of the complex changes from green to brown. Reduction of the cupric precatalyst with a substituted hydrazine results in a yellow cuprous complex capable of inducing an instantaneous decomposition of diazoacetate at ambient temperature. Aratani proposes that the active catalyst is tetrahedral Cu(I), 26 in Scheme 2. Reaction with the diazoester from the less hindered face forms the Cu carbenoid having one hemilabile ligand (al-... 

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