Surface residual stress in soda-lime glass evaluated using instrumented spherical indentation testing

Abstract

Instrumented spherical indentation testing is proposed as a non-destructive way to evaluate surface residual stress in soda-lime glass. 10 mu m-deep indentations with a spherical indenter of 250 mu m radius do not reduce the strength of 3.5-mm-thick soda-lime glass as measured in four-point bending tests. We find good linearity between the compressive surface residual stress and the force difference at maximum indentation depth in the indentation force-depth curve, while hardness as measured by instrumented spherical indentation testing is independent of compressive surface residual stress introduced by bending and strengthening heat treatment