Cooperative phenomena of random electric dipoles in an amorphous matrix

A ferroelectric phase transition has been observed for the first time in a series of glasses containing WO₆-octahedra. The techniques of thermally stimulated depolarization currents were used to observe the transition from independent dipole behavior to cooperative behavior in this amorphous system as a function of concentration. These measurements yielded the activation energy ΔE=1.2eV, the pre-exponential τ₀=2 × 10^-22sec, and the dipole moment p?=1.3 × 10^?15 esu cm for WO₃ in Li₂B₄O₇. A dipole moment bearing species due to Li₂B₄O₇ was observed with ΔE=0.44eV and pre-exponential τ₀=5 × 10^?8 sec. The depolarization peaks of WO₃ occur in the temperature range 265–275 K depending upon WO₃ concentration and are pressure dependent with an initial slope of 2 × 10^?5K dyne^?1 cm². A model was developed for a possible phase transition associated with a random “pseudo-spin” system in an amorphous matrix.