Photochromic Effect in Fe‐Doped PLZT Ceramics

Abstract

The photochromic effect in Fe‐doped transparent PLZT ceramics was investigated. The ceramics are darkened by irradiation with blue light having a wavelength of <4800 Å. The induced dark state is stable at room temperature and can easily be bleached back to its original transparent state by heat treatment at ∼200°C. The photo induced optical density change depends strongly on the transparency of the ceramic. Response times for the darkening and bleaching have been investigated as a function of the excitation light intensity and the temperature of the ceramic. A tentative model explaining the observed effect is proposed, and the photochromic mechanism is discussed on the basis of a charge‐transfer process between the photo activated Fe 3+ and Fe 4+ impurities in the ceramic.