| Popis: |
The role of three different adhesion promoters in the primary coatings of optical fibers on the resistance of fibers to aging in water has been investigated. The use of an acid phosphate ester as adhesion promoter gave fibers higher strength and n-value prior to aging when compared to standard silane adhesion promoters and copolymerizable silane coupling agents. After 6 months of zero stress aging in water of 60 degree(s)C, no change in strength was found for all fibers except for 1 fiber. The high n-value of fibers with the phosphate ester adhesion promoter gave fibers improved resistance (or longer time to failure) to high stresses in the static fatigue test in water of 85 degree(s)C. Tn this test, the time to failure for low applied stresses, where zero stress aging determines lifetime, was not depending on the type of adhesion promoter. other aspects of the coating as the level of adhesion to the glass, the chemical composition and the mechanical characteristics are playing a role as well in the resistance of fibers to stress free aging and static fatigue in water. |
