Radial distribution of fictive temperatures in silica optical fibers

The fictive temperature of glass samples influences many glass properties including mechanical strength and fatigue characteristics. A distribution in fictive temperature on a cross-section of a commercial silica glass communications fiber was determined by measuring the profile of the IR reflection band wavenumber of the silica fundamental structural band at similar to 1122 cm(-1) as a function of radial position using an FTIR with a microscope attachment. Results showed a lower peak wavenumber which corresponds to a higher fictive temperature near the surface of the as-received fiber, Upon annealing, this surface characteristic disappeared and a nearly constant peak wavenumber was obtained across the fiber cladding indicating that the high fictive temperature of the commercial fiber surface was produced during the fiber drawing process. The different mechanical fatigue behavior of silica fibers from those of bulk silica glasses may be due to the observed high fictive temperature of the fiber surface. (C) 1997 Elsevier Science B.V.