In this paper, the acoustoelasticity phenomenon is used in order to estimate the residual stress distribution by using acoustic surface wave. An experimental set-up based on a double interferometric detection in which an aspheric lens is associated with a beam splitter and a YAG laser whose power is 100 mW is presented. This relative high power enables the measurements to be carried out on surface flat glass although optical reflection coefficient is typically weak. Using these two points of detection, the evolution of relative surface wave velocity is obtained with good accuracy. A comparison between the numerical modelling & experimental results shows the potentiality of an ultrasonic method to estimate stress distribution in flat glass tempering.
