Scanning acoustic microscopy: a tool for measuring crosslinking gradients in photopolymer materials

The crosslinking gradients in photopolymer material having a curved surface can be determined by using acoustic techniques. The reflection coefficient at the liquid/material interfaces measured by low frequency microechograph y is related to the mechanical properties of the material and also the prof ile of the surface. This method makes it possible to take away the effect o f relief and local slope and easily to obtain a map of the mechanical prope rties, in particular of crosslinking density changes and a topography of th e surface. (C) 1999 Elsevier Science S.A. All rights reserved.