AbstractWhile the telecommunications optical fiber technology is in its third decade of growth, and fibers that are aging-resistant and fatigue-resistant are highly desirable, basic physico-chemical aspects of fiber aging and mechanical strength degradation are not well understood. A key difficulty to understanding fiber strength degradation has been the unavailability of tools for direct assessments of the condition of fiber coatings on aged fibers. In this presentation, we report on our studies of the effects of DI-water aging on two experimental high n-value (fatigue-resistant) fibers and their coatings. We have found that the coatings of these high n value fibers are highly resistant to DI-water aging.