Origin of microinhomogeneities in As-S-Se glass fibers fabricated by the double-crucible method

The optical losses in sulfoselenide glass fibers fabricated by the double-crucible method are shown to rise in going from the first-drawn portion to the back end of the fiber. Optical microscopy, IR and Raman spectroscopy, energy-dispersive x-ray microanalysis, and differential scanning calorimetry data indicate that fiber drawing is accompanied by the development of microinhomogeneities of the chemical and phase compositions of the melt, which are responsible for the increased scattering losses. The microinhomogeneities originate from phase segregation of the molten glass.