## 1 Introduction  
Silicon oxycarbides have been studied for several decades and attracted special attention due to the unique way in which they exhibit and combine structural features and properties of glasses with those of interface-dominated nano-heterogeneous materials [1]. Thus, silicon oxycarbide typically can be described as silicate glasses with strong carbon-for-oxygen substitution [2; 3]. The incorporation of carbon in the silica glass network has been shown in various studies to improve its properties. It was shown for instance that silicon oxycarbide glasses have significantly increased Young's moduli, hardness values, fracture toughness and devitrification resistance when compared to vitreous silica [1]. This effect has been attributed to an increased network connectivity of the silicon oxycarbides as compared to that of vitreous silica. Moreover, studies concerning the network architecture of silicon oxycarbide glasses revealed a relatively low mass fractal dimension of those materials (typically in the range of 2.3-2.5) [2], which has been reflected for instance in a very low Poisson ratio (i.e., 0.11 as compared to 0.17 in silica-based glasses) [4] and highly promising bioactivity with respect to hydroxyapatite mineralization [5; 6; 7]. The glassy network of silicon oxycarbides can be easily altered via incorporating additional network corners (i.e., boron) [8] or modifiers (e.g., Li, Ca, Mg, etc.) [3; 5; 6; 9; 10], thus structural properties such as network connectivity and polymerization can be finely tuned [6]. This allows for providing finely adjustable properties in silicon-oxycarbide-based materials. In addition to the unique structural architecture of their glassy network and their remarkable property profile correlated to it, silicon oxycarbides can be designed to contain an in situ formed sp\({}^{2}\)-hybridized carbon phase finely dispersed within their microstructure. This segregated carbon phase has been shown to be responsible for a plethora of interesting properties of silicon oxycarbides such as reversible Li uptake/release [11; 12; 13; 14; 15], tunable thermal and electrical transport [16; 17; 18], piezoresistive behavior [19; 20; 21], near-zero creep at high temperatures [22; 23; 24; 25], electromagnetic wave absorption [26], tailorable surface energy [27], adjustable blood clothing effect [28], etc. The amount of sp\({}^{2}\)-hybridized free carbon can be varied from a negligible fraction [29] up to very large extents by adjusting the macromolecular architecture of the preceramic polymers and by considering the introduction of additional carbon sources (e.g., divinyl benzene or other aromatics-containing compounds) either by blending or by chemical bonding [1; 30; 31]. Moreover, the synthesis temperature of free-carbon-containing silicon oxycarbides (i.e., SiOC/C) has been shown to directly correlate to the ordering degree (crystallinity) of the free carbon phase [32]. Thus, the sp\({}^{2}\)-hybridized carbon phase shows a highly disordered structure at temperatures of ca. 1000-1200 \({}^{\circ}\)C typically used for the synthesis of SiOC/C; whereas annealing of SiOC/C at higher temperatures leads to a significant ordering of the free carbon phase [1; 32]. As mentioned above, the concentration and ordering of carbon in silicon oxycarbides has been shown to directly affect their properties; for instance, the electrical conductivity in silicon oxycarbides can be progressively changed from an insulator to a semiconductor and semimetal [1]. As recently reported in a case study, SiOC/C with a carbon content of ca. 30 vol.%, which was prepared via pyrolysis of a preceramic polymer at 1000 \({}^{\circ}\)C showed a resistivity value of \(\rho\) = 0.35 \(\Omega\)/m, which further decreased to \(\rho\) = 0.14 \(\Omega\)/m upon pyrolysis at higher temperatures [33]; whereas a SiOC/C material derived from DVB-added polyhydridomethylsiloxane exhibited an even lower value of 0.23 \(\Omega\)/m [34] (note that graphite has a resistivity \(\leq\)10\({}^{-3}\)\(\Omega\)/m).