In　this　paper,　MnO2　is　added　to　CaO-SrO-B2O　3-SiO2　sealing　system　to　control　the　redox　glass/metal　interfacial　reaction　in　Solid　Oxide　Fuel　Cells.　The　effect　of　MnO2　dopant　on　the　valance　states　of　Mn　ions　in　glasses,　the　glass　structure　and　glass/metal　interfacial　reaction　is　systematically　investigated.　The　quenched　glasses　contain　Mn2+　ion　only;　whereas,　the　Mn3+　content　in　glasses,　held　at　600　°C　for　9　h,　increases　with　increasing　MnO　2　dopant.　The　good　bondage　can　be　observed　at　the　interfaces　between　Crofer　22APU　and　glass　containing　6　mol　%　MnO2,　held　at　700°C　for　500　h.　The　competitive　reaction　reduces　the　redox　chromate　formation　by　consuming　the　oxygen　at　the　glass/metal　interface.　In　addition,　the　competitive　reaction　results　in　the　formation　of　a　continuous　Mn-Cr　oxide　scale　at　the　glass/metal　interface,　which　is　helpful　for　reducing　the　further　diffusion　of　Cr　from　metallic　interconnect　to　glass.　©　2014　Elsevier　B.V.　All　rights　reserved.