Ydk03

The density ρ of the sintered glass parts was measured by the Archimedes principle using a lab scale Quintix 124‐1S and a density kit analytical balance YDK03 (Sartorius AG, Germany). The sintered fused silica parts were weighed in the dry state (m). Afterward, they were immersed in DI water (T = 20.5 °C) with a small amount of surfactant and the buoyancy mass m_b was determined. The density was calculated using following equation, with ρ_H2O being the density of water
$$\rho =\frac{m{\rho }_{{\mathrm{H}}_2\mathrm{O}}}{-m_{\mathrm{b}}}$$
The shrinkage was determined by measuring three different FDM‐printed parts in the green part stage and after sintering with a caliper. The theoretical linear shrinkage Y_s can be calculated in dependence of the solid loading Φ, theoretical density ρ_t, and final density ρ_f of the manufactured object using following equation
$$Y_{\mathrm{s}}=1-{\left(\frac{\mathrm{\Phi }}{{\rho }_{\mathrm{t}}/{\rho }_{\mathrm{f}}}\right)}^{\frac{1}{3}}$$
Optical inline transmission was determined by using a UV–vis spectrometer of type Evolution 201 (Thermo Scientific, Germany) and an FTIR spectrometer of type Frontier 100 MIR‐FTIR (Perkin Elmer, Germany). Total UV–vis transmission and reflectance were measured using a UV–vis–NIR spectrophotometer of type UV‐3600i Plus (Shimadzu, Japan) equipped with an integrating sphere attachment of type ISR‐1503 (Shimadzu, Japan). Fused silica glass slides (2 mm thickness, Toppan Photomasks, Inc., USA) were used as a reference sample for all measurements.