Sealing　glasses　for　solid　oxide　fuel　celss　must　initially　flow　sufficiently　to　produce　an　adequate　seal,　then　maintain　enough　rigidity　for　mechanical　integrity.　The　thermal　expansion　characterization　of　the　glass　should　be　compatible　with　other　SOFC　components,　and　the　glass　should　be　chemical　stable.　Over　80　compositions　based　on　modified　alkaline　earth　silicates　have　been　prepared　and　evaluated,　and　some　general　composition-property　trends　have　been　identified.　The　addition　of　B2O3　decreases　the　softening　temperature　as　well　as　the　glass　transition　temperature.　The　presence　of　ZnO　improves　the　sealing　condition　by　broadening　the　temperature　window　between　glass　transition　and　crystallization　up　to　230°C　with　high　Zn　content　(Zn/Si　molar　ratio=0.7).　The　coefficient　of　thermal　expansion　for　these　＇invert　glasses＇　depends　on　the　average　field　strength　of　RO.　The　addition　of　BaO　increases　the　CTE　of　glasses　due　to　the　low　field　strength　of　BaO.　The　addition　of　ZnO　decreases　the　CTE　of　glasses　due　to　the　increase　of　average　field　strength.