Abstract: A method of selecting poling parameters for poling a glass ceramic body comprising ferroelectric domains, by applying an electric field across the glass ceramic body at a certain poling temperature for a certain poling time comprises the steps of: determining an upper bound of poling temperature given by the maximum poling temperature at which uncontrolled heat-up (thermal runaway) is avoided; and selecting the poling temperature to be smaller than the upper bound, preferably close to the upper bound.

Abstract: A method of preparing a textured glass ceramic is disclosed which comprises the steps of preparing a precursor glass, preparing a precursor glass body, placing the precursor glass body in a furnace in contact with a brick body having a larger or smaller thermal capacity than formed by the precursor glass body, and ceraming the precursor glass body within the furnace in contact with the brick body thereby effecting a temperature gradient across the precursor glass body for precipitating crystallites having a preferred direction of orientation.

Abstract: A translucent piezoelectric glass ceramic is disclosed. The glass ceramic is prepared from a precursor glass by a ceraming process, using a temperature gradient to effect the precipitation of non-ferroelectric piezo-active crystallites from the precursor glass with a preferred direction of orientation and having an average crystal size of less than 1 micrometer. Alternatively, a translucent piezoelectric glass ceramic comprising ferroelectric crystallites may be prepared by poling. In this case the crystal size is controlled to be smaller than 90 nanometers but preferably larger than 10 nanometers.