Effect of pH on the Strength and Fatigue of Fused Silica Optical Fiber

The fatigue behavior of both bare and polymer coated silica optical fiber has been determined in various buffered pH solutions. Bare and polymer coated fibers were studied to distinguish any coating effects. Numerical integration techniques were utilized to fit the data to three kinetics models, and the fatigue parameters were calculated together with their corresponding confidence ellipses. The apparent reaction order for the reaction between the OH ion and SiO2 between pH 4 and pH 10 was determined to be ∼ 0.3 and this value is independent of the kinetics model used to fit to the data. The relationship between fatigue and pH is nonlinear; indicating different mechanisms at high, low, and intermediate pH.