The nucleation and crystallization kinetics of PbO–BaO–SrO–Nb2O5–B2O3–SiO2‐based glass–ceramics have been investigated. Strontium barium niobate (Sr0.33Ba0.67Nb2O6) with a tetragonal tungsten–bronze structure formed as the major crystalline phase, which nucleates and grows on the surface region of samples. The results of the present study showed an apparent activation energy of 193 kJ/mol for nucleation, which was controlled by the viscous flow of the glass. Quantitative X‐ray analysis and differential thermal analysis showed that the rate‐limiting mechanism of crystallization appeared to be a three‐dimensional interfacial growth, which has an apparent activation energy of 386–430 kJ/mol, a value that is close to the dissociation of Si–O bonds in the glass system.

The crystallization kinetics and phase developments of PbO–BaO–SrO–Nb2O5–B2O3–SiO2-based glass-ceramics was investigated. Lead strontium barium niobate, (Pb,Sr,Ba)Nb2O6, with a tetragonal tungsten-bronze structure formed as the major crystalline phase, which showed evidence of both surface and bulk crystallization. The results of the present study showed significant evidence of a change in crystallization mechanism between the as-heated surface and the interior of glass-ceramics. This effect could be attributed to a volatilization of PbO taken place readily on the surface region of sample during heating. The grain size of the bulk-nucleated (Pb,Sr,Ba)Nb2O6 crystals was substantially smaller than that of surface-nucleated crystals. This result facilitated meeting the capacitors as high energy density application due to the ultrafine grains (<60 nm) obtained. The dielectric constant increased from 27 for the as-quenched glass to 200 for a highly crystallized glass-ceramic, which was attributed to a significant volume fraction of (Pb, Sr, Ba) Nb2 O6 phase.