In this study, novel glasses based on SrO-La2O 3-Al2O3-B2O3-SiO 2 system are investigated for solid oxide fuel and electrolyzer cells. The network structure evolution of the glasses with increasing B 2O3:SiO2 ratio was studied using Raman spectroscopy. The thermal properties of the glasses, including glass transition temperature T g and glass softening temperature T d , were studied using dilatometry. The thermal stability of the glasses was investigated using X-ray diffraction. The study shows that as the B 2O3:SiO2 ratio increases, the SrO-La 2O3-Al2O3-B2O 3-SiO2 glass micro-heterogeneity and the amount of non-bridging oxygen atoms increase. Correspondingly, the T g of the SrO-La2O3-Al2O3-B2O 3-SiO2 glasses changes from 635 to 775°C, and the T d changes from 670 to 815°C. Glass thermal stability decreases with B2O3:SiO2 ratio increase. The glass without B2O3 is thermally stable after being kept at 850°C for 200 hrs. © 2008 Springer-Verlag.