Defect-driven reversible photochromism and green luminescence modulation in Tb3+ doped cadmium-based glass for optical information storage

With the advancement of modern optics and information technology, luminescent reversible photochromic transparent glasses have attracted considerable attention due to their potential for multimodal data storage. Cadmium-based glasses exhibit excellent photochromic performance, however, their underlying mechanism remains insufficiently elucidated. In this work, Tb 3+ -doped transparent cadmium glass was fabricated, which underwent a rapid transition from transparent to dark brown within 60 s under 365 nm UV irradiation, and completely recovered to transparency upon thermal treatment at 200 ℃, demonstrating high reversibility and cycling stability. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analyses revealed that the photochromism is primarily governed by oxygen-vacancy-related color centers, wherein Cd sites serve as electron-enriched centers while Pb-O environments accommodate localized holes. Their spatially coupled charge compensation stabilizes the color centers and sustains reversibility. On this basis, reversible modulation of Tb 3+ luminescence was achieved, with a maximum emission contrast of 93.9 %. This study clarifies the mechanism of cadmium-based photochromic glass from the perspective of defect-charge compensation and provides insights into the design of multifunctional glasses for optical information storage.