Temperature dependence of the ability of optical glass to withstand 10-msec laser pulses

A determination was made of the temperatures in the focal region of a lens just before laser damage to homogeneous regions in the interior and on the surface of K-8 glass. The softening temperature was also determined. A preliminary heating of the surface to ~600°C reduced considerably the number of defects formed by the mechanical treatment of the surface. The threshold damage temperatures of the surface and interior of the glass corresponded to the onset of formation of bubbles of the gas dissolved in the glass.