Glasses in the ZnO-B 2 O 3 -MO 3 (M = W, Mo) ternary were examined as potential replacements to PbO-B 2 O 3 -SiO 2 -ZnO glass frits with the low firing temperature (500-600 • C) for the dielectric layer of a plasma display panels (PDPs). Glasses were melted in air at 950-1150 • C in a narrow region of the ternary using standard reagent grade materials. The glasses were evaluated for glass transition temperature (T g ), softening temperature (T d ), the coefficient of thermal expansion (CTE), dielectric constant (ε r ), and optical property. The glass transition temperature of the glasses varied between 470 and 560 • C. The coefficient of thermal expansion and the dielectric constant of the glasses were in the range of 5-8 × 10 −6 / • C and 8-10, respectively. The addition of MO 3 to ZnO-B 2 O 3 binary could induce the expansion of glass forming region, the reduction of T g and the increase in the CTE and the dielectric constant of the glasses. Also, the effect of the addition of MO 3 to ZnO-B 2 O 3 binary on the transmittance in the visible-light region (350-700 nm) was investigated.