The aim of this work as a part of a framework programme for the investigation of structure-property relations in polymer matrix composites is the local characterization of interphase properties in composites comparing different techniques. The topic of this paper is to report first experimental results on the still remaining key question about the nature and extent of interphase zones. Since the bond strength is controlled by the matrix material adjacent to the fibre, i.e. the fibre-matrix interphase region, the local material data are needed to improve the models for the prediction of composites performance. The experimental work has been focused on epoxy resin/glass fibre model composites.