Collaborative Research: Elucidating the Atomic Origin and Mechanism of Relaxation in Silicate Glasses

非技术描述：玻璃不断地松弛到更稳定的状态，这可能会导致用作保护罩屏幕、平板显示基板或构成互联网主干的玻璃光纤的高科技玻璃产生不希望看到的老化效应。尽管最近在宏观尺度上描述玻璃弛豫取得了进展，但对玻璃弛豫的原子尺度本质仍知之甚少。为了解决这一认识上的差距，该项目旨在阐明玻璃弛豫的原子起源和机制。这些基本的见解将促进理性的、非经验的新型玻璃的设计，使其具有更好的抗老化效应的稳定性。通过将实验、模拟和理论无缝集成，这个合作项目旨在培养学生精通与材料科学和工程相关的实验和建模方法，特别是工业玻璃。该项目特别注重吸引、吸引、发展和留住工程领域的女学生，以纠正性别失衡。此外，该项目旨在让宾夕法尼亚州农村地区当地初中和高中的学生了解材料在我们社会中的关键作用。技术细节：这项研究的目的是在原子尺度上研究玻璃弛豫的性质。这个项目的目的是：(I)探索不同温度下不同弛豫模式之间的联系，(Ii)破译原子拓扑在控制弛豫倾向方面的作用，以及(Iii)揭示玻璃弛豫的结构机制。这项研究依赖于精心控制的实验和原子模拟的战略组合--在这种组合中，实验和模拟活动相互告知并相互提供信息。这个项目是及时的，因为它依赖于一种新的加速模拟技术来通过建模获得长期的弛豫效应，以及强大的实验技术(例如X射线光子相关光谱和垂直扫描干涉测量)来研究低温玻璃弛豫的性质，并培训学生使用尖端材料表征和建模研究技术。实验和计算方法之间的协同作用是评估玻璃态深处是否存在弛豫的关键，从而质疑玻璃态的本质概念。该项目还对硅酸盐玻璃中的“中间相”的概念进行了质疑，预计松弛将被降至最低。总体而言，这个项目解决了玻璃科学中广泛的、基本的、尚未回答的问题，在基础和实践层面都具有重要的影响，因为弛豫是玻璃物理和化学交叉领域最关键的问题之一。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: A glass is continually relaxing toward more stable states, which can result in undesirable aging effects in the high-tech glasses used as protective cover screens, flat panel display substrates, or the glass optical fibers that form the backbone of the Internet. Despite recent progress in describing glass relaxation at the macroscale, the atomic scale nature of glass relaxation remains poorly understood. To address this gap in knowledge, this project aims to elucidate the atomic origin and mechanisms of glass relaxation. Such fundamental insights would facilitate the rational, non-empirical design of novel glasses with improved stability against aging effects. By seamlessly integrating experiments, simulations, and theory, this collaborative project aims to train students to be well-versed in both experimental and modeling approaches relevant to materials science and engineering, with particular focus on industrial glasses. This project places a special focus on attracting, engaging, developing, and retaining female students in engineering careers to rectify the gender imbalance. In addition, this project seeks to expose students from local middle and high school in rural areas in Pennsylvania to the crucial role of materials in our society. TECHNICAL DETAILS: The objective of this research is to investigate the nature of glass relaxation at the atomic scale. This project aims to: (i) explore the linkages between distinct modes of relaxation under different regimes of temperature, (ii) decode the role of the atomic topology in controlling the propensity for relaxation, and (iii) reveal the structural mechanisms of glass relaxation. This research relies on a strategic combination of carefully-controlled experiments and atomistic simulations -wherein experimental and simulation activities mutually inform and feed into each other. This project is timely as it relies on a new accelerated simulation technique to access long-term relaxation effects through modeling, as well as powerful experimental techniques (e.g., X-ray photon correlation spectroscopy and vertical scanning interferometry) to investigate the nature of glass relaxation at low-temperature and train students in cutting-edge materials characterization and modeling research techniques. The synergy between experimental and computational approaches is key to assess the existence of relaxation deep within the glassy state, thereby questioning the conception of the very nature of the glassy state. This project also interrogates the concept of "intermediate phase" in silicate glasses, wherein relaxation is expected to be minimized. Overall, this project addresses broad, fundamental, yet unanswered questions in glass science, with important implications both at the fundamental and practical levels, as relaxation is one of the most critical problems at the intersection between glass physics and chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.