Scientists at TU Dortmund University, Paderborn University, the University of Duisburg-Essen, and the University of Oxford have developed a method to control glass properties during manufacturing by adding a molecule called 1,10-phenanthroline to molten material. The research, published in Nature Materials, shows that this molecule performs two functions: it lowers the melting temperature and rearranges how metal atoms bond with surrounding molecules.
Prof. Dr. Sebastian Henke from TU Dortmund University led the study. He explains that the molecule "enters into a reaction" during the melting process rather than simply acting as a filler. As it binds strongly to metal centers, it increases the number of neighboring atoms around each metal atom, triggering a substantial reorganization of the glass structure.
The approach solves a longstanding manufacturing problem. Some specialized glasses break down at the temperatures normally needed to melt them, producing unwanted impurities. By melting at lower temperatures, the new method keeps the glass chemically stable. Prof. Dr. Matthias Bauer from Paderborn University notes that "this gentler process prevents the formation of harmful decomposition products," which is particularly important when studying magnetic properties.
The researchers used X-ray absorption spectroscopy to verify the structural changes. Although cobalt atoms in the glass maintained the same oxidation state, their local surroundings changed considerably as bonds reorganized around the added phenanthroline.
The technique worked beyond the original materials tested, suggesting it could apply to a broader range of glass materials. Prof. Henke states that "the melt is no longer a rigid intermediate state. It becomes a reaction space in which we can program the structure." Potential applications include catalysts, sensors, optoelectronic devices, and materials that control magnetic behavior or manipulate light.