2.1. Material Fabrication

To evaluate the effect of CaF₂ addition to BaG networks and to validate the fabrication protocol, a reference composition of BaG was employed [27]. BaG-F samples with varying F content were synthesized (Table 1).

Chemical compositions of fluorine bioactive glass (BaG-F_x: 0 < x < 20 wt.%).

Appropriate contents of sodium metasilicate pentahydrate (Na₂SiO₃-5H₂O, Aldrich, Darmstadt, Germany), CaF₂ (Merck, Darmstadt, Germany), calcium metasilicate (CaSiO₃, Merck, Darmstadt, Germany), sodium metaphosphate (Na₃P₃O₉, Aldrich, Darmstadt, Germany) and calcium carbonate (CaCO₃, Merck) were thoroughly mixed, and then subjected to a suitable thermal cycle (Figure 1). The molten vitreous material was then tempered in a preheated mold and annealed for 4 h at a temperature near to its glass transition temperature (Tg).

Thermal cycles used for bioactive glass (BaG)-based sensor. Some icons were taken from Biorender.com.