This study investigates Bi2O3-B2O3-BaO-ZnO glass with variations of the Co3O4 content (0.25,0.5,1,and 2wt%) and the interaction between transparent dielectric and Ag electrodes heat-treated at 500-560oC for30min. The glass transition temperature, softening temperature and thermal expansion coefficient were432oC, 460oC and 81.4×10-7/oC, respectively. The transmittance of 0.25wt% Co3O4 to which dielectric wasadded was highest and was decreased due to coloration with the addition of more than 0.25wt%. However,without Co3O4, the transmittance of the transparent layer was decreased due to the formation of Ba5Bi3;however, the occurrence of the crystal phase decreased as a result of the addition of Co3O4. The amount ofCo2+ ions increased as the Co3O4 increased. With a maximum of Co3+ ions, the highest transmittance wasobserved.