In planar solid oxide fuel and electrolyzer cells, compatibility and thermochemical stability of interconnect-seal glass interface is essential in order to avoid mixing and leakage of different gases and degradation of cell performances. In the present work, interfacial compatibility and thermochemical stability are studied for an alkaline earth silicate based glass (SABS-0) and Crofer 22 APU interconnect system with respect to thermal treatment temperature (700-850 °C) and time (0-100 h). The study has been carried out in argon to avoid complications from oxidation. Even though pore and crack-free interface is obtained and maintained for all the thermal treatment conditions, there are simultaneous diffusion of the Crofer 22 APU and the SABS-0 glass elements, chemical reaction at the Crofer 22 APU/SABS-0 interface, and devitrification of the SABS-0 glass itself. © 2009 Springer Science+Business Media, LLC.