Scattering characteristics in reheated fluorozirconate glasses

The relation between the scattering intensity and reheating conditions in fluorozirconate glasses was studied precisely to clarify the effect of devitrification induced by fiber drawing using the preform method. The drawing-induced scattering is substantially caused by the nucleation of microcrystallites and begins to increase at a temperature lower than that predicted by DTA or DSC measurements. Nevertheless, it is revealed that ultralow-loss fluoride glass fibers can be drawn without excess loss increase by the perform method under optimized glass compositions and reheating conditions.