Surface characterization and depth profile analysis of glasses by r.f. GDOES

International audience; The characterization of surfaces, interfaces and interphases in glasses is analytically challenging and may benefit from recent developments in radiofrequency glow discharge optical emission spectroscopy (r.f. GDOES) applied to non-conductive materials. Thus, the main thrust of this study is to evaluate the potential of r.f. GDOES for the characterization of glass surfaces, physical heterogeneities such as discrete layers and continuous interphases and the distribution of elements in glass materials. Model glasses with increasing structural and chemical complexity thus were analysed using a Jobin Yvon GDOES system (5000 RF): the glasses included a multilayered glass (triple-coated glass), two photoreactive glasses (with potential chemical diffusion gradients) and acid-leached glass with an alteration layer. Concurrently, surface characterization of the glasses was conducted using scanning electron microscopy or transmission electron microscopy with energy-dispersive x-ray imaging to assess the chemical and physical gradients in the materials and to investigate the glow discharge sputtering process. From this the capability of r.f. GDOES for elemental depth profiling in glass materials is established. However, although the sputtering rates for glass are greatly reduced compared with conductive materials (∼2 nm s−1 compared with 50–150 nm s−1 for metals), r.f. GDOES offers good spatial depth resolution (nm) and elemental sensitivity for several applications, such as the characterization of interfaces or interphases and the determination of chemical gradients in glasses. Furthermore, the technique distinguishes submicrometre discrete layers in the coated glass, and the diffusion of elements within glass matrices may be monitored.