Post-glass melting synthesis and photochromic properties of composite AgCl-AgPO3 glasses

We herein present a simple, fast, low-temperature, post-glass melting fabrication protocol in which a photochromic silver cation based modified zone is incorporated within silver metaphosphate glass (AgPO3). The selection of AgPO3 glass is mainly based on its relative "soft" nature (Tg = 192 oC) that enables the integration of silver cations from the surface deposited AgCl layer, while being transparent in most of the visible range, and therefore suitable for smart photochromic window applications. The suggested synthesis procedure permits the controlled formation of a silver cation modified layer within the host glass matrix, while the characteristics of the layer itself can be adjusted correspondingly. Our findings reveal a direct relationship between the developed composite AgCl–AgPO3 glass photochromic response and the morphological features of the integrated layer, i.e., thickness and position. More importantly, the photochromic response time with various UV irradiation doses is also studied, where remarkable response times of several seconds are obtained. Processes and efforts to further enhance the photochromic performance by utilizing the presence of silver nanoparticles within the glass matrix are also presented and discussed.