Thermal radiation characteristics and energy efficiency optimization of Li ₂ O–ZnO–SiO ₂ microcrystalline glass for building applications

Lithium zinc silicate (Li2O–ZnO–SiO2) microcrystalline glass is a promising energy-saving material for building applications, yet its thermal radiation behavior under dynamic heating conditions – critical for real-world performance – has not been systematically addressed. This study, for the first time, investigates the dynamic thermal radiation characteristics of Li2O–ZnO–SiO2 glass-ceramics during continuous heating from room temperature to 800°C, directly correlating real-time spectral emissivity with in-situ crystallization processes. By integrating high-temperature X-ray diffraction (HT-XRD) and emissivity measurements, we reveal that the onset of crystallization (notably Li2Si2O5 and Zn2SiO4 phases) triggers a pronounced, non-linear increase in total hemispherical emissivity – from ~0.25 in the glassy state to over 0.70 in the fully crystallized state. This work establishes a novel link between microstructural evolution and dynamic radiative properties, providing essential insights for the rational design of smart glazing and passive radiative cooling materials for sustainable construction.