Uncovering the thermolysis conversion mechanisms of 3D nanoprinted silica glass

Thermal conversion post-processing routes expand two-photon polymerization (2PP) 3D printing from polymers to inorganics, enabling free-form micro- and nanostructures from a growing bandwidth of glasses, ceramics and metals. Yet, limited knowledge on precise transformation mechanisms remains a key obstacle to advancing the approach towards widespread applicability. This paper establishes a fundamental understanding of the thermal conversion manufacturing of silica glass from hybrid organic-inorganic preforms, 2PP-printed from a polyhedral oligomeric silsesquioxane (POSS) feedstock resist. We present correlated thermal, mechanical, and spectroscopic analyses, which resolve key microstructural transformations and resulting dimensional, chromatic and mechanical mechanisms. The thermolysis accesses a wide range of mechanical properties from compliant rubber-like to ceramic-hard with an ultra-high tensile strength of 6 GPa. The introduced correlative methodology and obtained understanding are expected to translate across different routes, providing fundamental groundwork for the rational design of advanced thermal conversion protocols for the precision manufacturing of 3D high-fidelity structures.