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Glass samples with composition (35 - X) B2O3 - (40 + X) PbO - 25 TiO2 (where X = 0, 2.5, 5, 7.5 and 10 mol %) were prepared using conventional quenching technique. It was observed that as PbO content increases the value of Tcand Tc decreases. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The density values of glass ceramic samples are higher than those of corresponding glass samples. It was observed that there was good correlation between the density and CTE results of the glass-ceramics. The XRD results revealed the formation of tetragonal lead titanate as a major crystalline phase in the glass ceramics. The dielectric constant of glass ceramic samples is higher than those of corresponding glasses [ABSTRACT FROM AUTHOR]

Glass samples with composition (50 - X) PbO - X MO - 25 TiO2 - 25B2O3 (where X = 0, 5, 10 and 15 mol % and M = Ba, Sr) were prepared using conventional quenching technique. It has been observed that the addition of MO to PbO - TiO2 - B2O3, enhances the Tg. The rise in Tg with MO content may be attributed to the greater field strength of M2+ cation which leads to the formation of stronger bonds. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The XRD results revealed the formation of tetragonal lead titanate as a major crystalline phase in the glass ceramics. The addition of MO to the glass, contributes to the formation of secondary crystalline phases BaB2O4, Sr2B2O5. The ferroelectric nature of all the glass ceramic samples is confirmed by P - E hysteresis measurements. [ABSTRACT FROM AUTHOR]

Glass samples with composition (35- X) B2O3 - (40 +X) PbO - 25 TiO2 (where X= 0, 2.5,5, 7.5 and 10 mol %) were prepared using conventional quenching technique. It was observed that as PbO content increases the values glass transition temperature (Tg) and crystallization temperature (Tc) decreases. The replacement of boron by a bigger Pb ion expands the network there by reducing the glass transition temperature (Tg). These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The density(ρ) values of glass ceramic samples are higher than those of corresponding glass samples. It was observed that there was good correlation between the density and Coefficient of Thermal Expansion (CTE) results of the glass–ceramics. The XRD results in the glass ceramics revealed the formation of tetragonal lead titanate (PbTiO3) as a major crystalline phase and lead borate (PbB2O4) as minor crystalline phase. The microstructure of glass ceramic samples contains nano crystallites of lead titanate embedded in a borate glass matrix. As the content of glass former (B2O3) is reduced, the PbTiO3 crystals precipitated in glass matrix are observed to increase. The dielectric constant values of glass ceramic samples are higher than those of corresponding glass samples. [ABSTRACT FROM AUTHOR]

Glass samples with composition (50 - X) PbO - XCaO - 25 TiO2 - 25 B2O3 (where = 0, .5, 10 and 15 mol %) were prepared using conventional quenching technique. It was observed that with the addition of alkaline earth oxides to lead borate glass containing TiO2 alters the network (conversion of BO3 to BO4) increasing the rigidity of the glass which enhances the Tg. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The density values of glass ceramic samples are higher than those of corresponding glass samples. It was observed that there was good correlation between the density and CTE results of the glass-ceramics. The XRD results in the glass ceramics revealed the formation of tetragonal lead titanate as a major crystalline phase and Ca3Ti2O7 as minor crystalline phase. The ferroelectric nature of all the glass ceramic samples is confirmed by P - E hysteresis measurements. [ABSTRACT FROM AUTHOR]