The response of glass to mechanical contact has been the subject of numerous publications. However, most of these were dedicated to standard window glasses, although there is a need for the characterization of functional glasses such as chalcogenide glasses and of newly developed structural glasses such as oxycarbide glasses. Besides, most investigators focused on the phenomenology and on the mechanics of contact damage and the incidences of the glass composition and the environment were little studied and thus remain poorly understood. In this paper, it is intended to show the importance of the glass composition through several examples. Silicon oxycarbide and a series of soda-lime-silica glasses with different silica contents provide interesting illustrations of the effect of the network polymerization degree and of the compactness on the indentation behaviour.
