Structure–property relationships in the electrostriction response of low dielectric permittivity silicate glasses

Some of the polarization mechanisms that affect the dielectric and electrostrictive responses of low dielectric permittivity glasses are examined in this work. Electrostriction is the basic electromechanical coupling mechanism in all insulators. It is defined as xij = QijklPkPl, where xij is the strain tensor, Qijkl the electrostriction tensor, and Pk the induced polarization. The electrostriction constant Q11 (in Voigt notation) for glasses containing sodium was found to decrease with frequency in the range 0.1–10 kHz. Q11 decreased with frequency from 0.95 to 0.55 m4/C2 for sodium trisilicate glass and from 0.6 to 0.45 m4/C2 for sodium aluminosilicate glass. In contrast, the Q11 for two samples of silica glass remained nearly constant at ∼0.4 m4/C2 in this frequency range. The role played by the Na+ ion and that of silicate coordination shells in effecting the different electrostrictive responses of these glasses was analyzed.