Tensile stress-acceleration of the surface structural relaxation of SiO2 optical fibers

The surface relaxation kinetics of commercial silica optical fibers were studied by measuring the IR band positions in reflection, which are directly correlated with the Si-O-Si bond angle as well as the fictive temperature of the glass. The silica glass optical fibers were heat-treated at 650 degrees C under 355 torr water vapor pressure and dry nitrogen atmosphere with and without applied stress. It was found that the relaxation kinetics were measurably accelerated by a tensile stress in the presence of water vapor. (C) 1997 Elsevier Science B.V.