Thermal stability of specialty optical fiber coatings

Thermal stability of coatings used on specialty optical fibers is assessed via thermogravimetry (TG). The coating lifetimes are evaluated by analyzing dynamic TG curves and assuming a particular level of mass loss as a failure criterion. The studied coating systems include single and dual acrylate, fluorinated acrylate, epoxy, epoxy acrylate, silicone, silicone acrylate, silsesquioxane acrylate and polyimide materials. Processing the data by Arrhenius and Eyring equations indicates that a kinetic compensation effect (KCE) is observed for the decomposition processes, with distinct parameters for different classes of the coatings. Two aspects of the KCE are considered: (1) decomposition within several series of similar compounds in air and (2) decomposition of the same classes in different environments. An attempt is made to use the KCE to predict the lifetimes of the coatings at elevated temperatures.