Understanding the impact of boron on glass surface properties is an ongoing challenge in the development of novel technical glasses. Prior work has shown that the behavior of boron is often linked to its structural coordination environment—a fact well-established in bulk glass properties, but also observed with surface reactivity. Here, we interrogate the coordination state of boron at the surfaces of a span of sodium borosilicate and boroaluminosilicate glasses using B K-edge NEXAFS spectroscopy. After considering both beam-damage and surface preparation effects, we examine results for surface coordination state as a function of composition, and contrast results against bulk coordination determined by ¹¹B NMR spectroscopy. Key results show deviation from the principles that govern bulk structure, with a preference to form 4-coordinated species at the surface—likely from interaction with ambient moisture—and correlated with the presence of 3-coordinated boron with NBO in the bulk.

理解硼对玻璃表面性能的影响是新型技术玻璃发展中的一项持续挑战。先前的研究表明，硼的行为通常与其结构配位环境有关，这一事实在大块玻璃的性能中已得到充分证实，但也具有表面反应性。在这里，我们使用B K-edge NEXAFS光谱仪在硼硅酸钠玻璃和硼铝硅酸盐玻璃的表面上询问硼的配位态。在考虑了光束损伤和表面处理效果之后，我们检查了表面配位状态的结果与成分的关系，并对比了由¹¹确定的相对于本体配位的结果B NMR光谱。关键结果表明偏离了控制本体结构的原理，偏向于在表面形成4位配位物种（可能是由于与环境水分的相互作用），并且与3位配位硼与NBO的存在相关。