NOVELTY - Sealing (M1) two inorganic substrates together using a microwave energy source involves: a) providing first and second inorganic substrates; b) applying to at least one of first and second substrates a paste composition including a glass frit, and a microwave coupling additive; c) arranging the substrates such that the paste composition lies between them and in contact with both substrates; and d) subjecting the substrates and paste to microwave radiation, thereby forming a hermetic seal between the two inorganic substrates.    USE - For sealing two inorganic substrates together using a microwave energy source; for forming a hermetically sealed cavity; and for bonding first and second glass plates to one another, so as to hermetically seal and isolate a cavity defined between them (claimed). The hermetic seals are useful in various applications such as encapsulating solar cells based on silicon, organic systems, and thin film; encapsulating other electronic devices such as organic LEDs (OLED); producing Vacuum Insulated Glass (VIG) windows; and architectural windows and automotive glass.    ADVANTAGE - The method prevent stresses that would weaken the seal and prevent fractures that would compromise the hermeticity of the seal. This is done by controlling the composition of the enamel and the parameters of the sealing technique. The use of preglazed enamels is extremely helpful for forming high-quality hermetic seals. The use of dried enamels for the sealing step results in significant dimensional changes when the coating has a substantial thickness, making formation of the seal more difficult. In addition, the dried enamels are prone to form large voids in the seal, and also tend to blow some contamination to the inside of the cell module or VIG panel during the sealing method.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a lead-free and cadmium-free sealing glass composition, comprising, prior to firing: Bi2O3 (25-65 mol%); ZnO (3-60 mol%); B2O3 (4-65 mol%); 0.1-15 mol% of at least one selected from the group consisting of CuO, Fe2O3, Co2O3, Cr2O3; no intentionally added oxides of silicon; and no intentionally added oxides of aluminum;    (2) forming (M2) a hermetically sealed cavity involving: (a) providing at least two glass plates; (b) applying a glass composition selected from glass 1 containing Bi2O3 (25-65 mol%), ZnO (3-60 mol%), B2O3 (4-65 mol%), at least one (0.1-15 mol%) selected from CuO, Fe2O3, Co2O3, Cr2O3, no intentionally added oxides of silicon, and no intentionally added oxides of aluminum; glass 2 containing Bi2O3 (37-45 mol%), ZnO (30-40 mol%), B2O3 (18-35 mol%), at least one (0.1-15 mol%) selected from CuO, Fe2O3, Co2O3, Cr2O3, no intentionally added oxides of silicon, and no intentionally added oxides of aluminum; glass 3 containing ZnO (5-65 mol%), SiO2 (10-65 mol%), B2O3+Al2O3 (5-55 mol%), and at least one selected from at least one (0.1-45 mol%) selected from Li2O, Na2O, K2O, and Cs2O; at least one (0.1-20 mol%) selected from MgO, CaO, BaO, and SrO, and at least one (0.1-40 mol%) selected from TeO2, Tl2O, V2O5, Ta2O5, GeO2; (c) bringing at least a second glass plate into contact with the glass composition into physical contact with one another; and (d) subjecting the glass composition to microwave heating to sinter and flow the glass composition to thereby form a hermetic seal; and    (3) bonding (M3) first and second glass plates to one another, so as to hermetically seal and isolate a cavity defined between them, involving: (a) providing a first homogeneous powder glass sealing composition comprising Bi2O3 (25-65 mol%), ZnO (3-60 mol%), B2O3 (4-65 mol%), no intentionally added oxides of silicon, and no intentionally added oxides of aluminum; (b) providing a second homogeneous powder glass sealing composition comprising Bi2O3 (37-45 mol%), ZnO (30-40 mol%), B2O3 (18-35 mol%), at least one (0.1-15 mol%) selected from CuO, Fe2O3, Co2O3, Cr2O3, no intentionally added oxides of silicon, and no intentionally added oxides of aluminum; (c) mixing the first and second powders form a homogeneous mixture; (d) applying the homogeneous mixture to at least one of the first and second glass plates; (e) positioning the first and second glass plates such that the first and second powders come into contact with both glass plates; and (f) subjecting the glass plates and powders to microwave heating with an electromagnetic field having a frequency of 0.9-2.5 GHZ, to sinter and flow the first and second powders thereby forming a hermetic seal defining a cavity between the first and second plates.