In this study the high temperature stability (crystallization and decomposition) of two silicon oxycarbide glasses with a similar amount of free carbon (8.3 vs 9.6 wt%) but different content of Si‐C bonds (SiC_0.22O_1.57 vs SiC_0.07O_1.86) is presented. The two SiOC glasses are obtained from the same precursor (2 µm methyl‐silsesquioxane spheres) via pyrolysis at 1100°C in inert (Ar) or reactive (CO₂) atmospheres. Further annealing in Ar flow at temperatures above 1100°C and up to 1500°C is performed and the samples are characterized by Fourier Transformed Infrared Spectroscopy (FT‐IR) and X‐ray diffraction (XRD). For comparison purposes the same precursor was annealed in air flow to obtain SiO₂ and its high temperature evolution is also studied. Results suggest that the onset for the carbothermal reduction is not dependent on the amount of Si‐C bonds. Moreover, contrary to what is usually reported in the scientific literature, silica phase present in the SiOC glasses does not show, in the same experimental conditions, superior crystallization resistance compared to pure silica glass.

中文翻译：

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阴离子取代对源自聚合物的SiOC玻璃的高温稳定性的影响

在这项研究中，两种具有相同游离碳量（8.3 vs 9.6 wt％）但具有不同Si-C键含量（SiC _0.22 O _1.57 vs SiC _0.07 O _1.86）的碳氧化硅玻璃的高温稳定性（结晶和分解）被表达。通过相同的前体（2 µm甲基倍半硅氧烷球体），通过在惰性（Ar）或反应性（CO ₂）气氛中于1100°C进行热解获得了两种SiOC玻璃。在高于1100°C且最高1500°C的温度下在Ar流中进行进一步退火，并通过傅里叶变换红外光谱（FT-IR）和X射线衍射（XRD）对样品进行表征。为了比较，将相同的前体在气流中退火以获得SiO ₂并对其高温演化进行了研究。结果表明，碳热还原的开始与Si-C键的数量无关。此外，与科学文献中通常报道的相反，在相同的实验条件下，SiOC玻璃中存在的二氧化硅相没有显示出比纯二氧化硅玻璃优越的抗结晶性。