Determination of Axial Stress in Clad Glass Fibers

The axial stress in clad glass fibers was measured by photoelastic techniques and compared with calculated values. In general, there was good agreement when the hydrostatic stress development was included in the calculation. The systems studied were primarily those which would produce a surface compression. Fibers of a soda‐lime‐silica glass clad with a high‐silica glass gave the largest surface compression, 46,000 psi.