Effect of Porosity on Compressibility of Glass

Abstract

An expression derived for the compressibility of glass foams is the same as Mackenzie's expression for a body containing a low concentration of spherical pores, when carried to the limit of very high porosity. Simple analysis shows that Mackenzie's expression is also valid for slightly nonspherical pores but should underestimate the actual compressibility for porosities which are neither high nor low. Compressibility measured on a series of porous glass samples to 70% porosity agree closely with the theoretical relation, except at intermediate porosities, where the departure shows the predicted effect of pore interaction.