Abstract Radiation induced during ion-beam bombardment of solids by energetic ions consists mainly of characteristic lines of the spectra of excited free atoms or ions sputtered from the target. These characteristic lines can be applied for analysis of the material under investigation. A simple apparatus is described for the investigations at glass surfaces and thin film systems. Changes of concentration of a single constituent are indicated in the intensity versus time plots recorded for a single characteristics line of this constituent by changes of the intensity qualitatively. In-depth changes of the real concentration can be obtained quantitatively from the recorded intensity changes by calibration. The in-depth resolution is of the order of some tens of angstroms. The method was applied to investigate interdiffusion between the Si of a thin SiO 2 surface layer and of Pb and B within the substrate glass. Extensive investigations of the intensity/time plots obtained from Na 2 O-containing glass surface layers or bulk glasses illustrate the influence on the results due to the special disintegration processes caused by a beam of ions at the bombarded surface.