Abstract: Polar piezoelectric glass-ceramics of composition Ba_2-xSr_xTiSi₂O₈ with c-axis oriented growth
were prepared by crystallizing the BaO-SrO-TiO₂-SiO₂ glasses in a high temperature gradient. The structure was determined by XRD and SEM. The
physical model of driving force of the polar piezoelectric Ba_2-xSr_xTiSi₂O₈ crystal along c-axis dimension was set up,
in accord with the experiment. The results show that the c-axis oriented growth of polar crystal is synchronously driven by gradient of temperature, dipole field and c-axis maximum energy of crystal lattice. The interior
driving forces are both the difference of energy of ionic crystal lattice in different axis and dipole field produced by spontaneous polarization of polar
crystal. The exterior driving force is the gradient of temperature.

Key words: polar crystal, driving force, piezoelectricity, growth along one dimension