Scientists have developed a new way to change the internal structure of glass while it is being made, giving them greater control over properties such as magnetism and the way the material interacts with light. The discovery could open the door to advanced glasses with capabilities that were previously difficult or impossible to achieve.
The breakthrough comes from a collaboration involving TU Dortmund University, Paderborn University, the University of Duisburg-Essen, and the University of Oxford. Published in Nature Materialsthe research demonstrates how adding a particular organic molecule during the melting process can rearrange chemical bonds within certain types of glass.
The method also allows these materials to melt at much lower temperatures, preventing the damage that would otherwise occur during manufacturing. Such specialized glasses have potential applications in gas storage, batteries, optical technologies, and catalysis.
A Molecular Trick That Changes Glass From Within
“We have found a way to chemically modify the structure of glasses derived from so-called metal-organic framework compounds – or MOFs for short – right during the manufacturing process,” explains Prof. Dr. Sebastian Henke from TU Dortmund University, who led the study.
The key ingredient is a molecule called 1,10-phenanthroline. When introduced during production, it performs two important tasks. It reduces the temperature needed to melt the material while also changing how metal atoms connect with surrounding molecules.
This combination allows researchers to create glass with magnetic or light-emitting characteristics that previously could not be achieved without exposing the material to potentially destructive temperatures.
Rewriting the Chemistry of Molten Glass
To understand why this approach matters, it helps to consider how glass normally forms. When a liquid cools quickly enough, its atoms become locked into a disordered arrangement rather than forming the repeating pattern found in crystals.
“Normally, glass is formed when a molten liquid cools rapidly. The solid structure then sets without the atoms arranging themselves in a regular pattern. Until now, researchers often had to accept the chemistry of these glasses as dictated by the starting material,” explains Prof. Henke.
The new findings show that scientists can exert much greater control over this process.
Metal-organic frameworks are materials built from metal centers connected by organic compounds. By introducing phenanthroline while these materials are molten, researchers can change the chemical connections within the structure before the glass solidifies.
“The crucial point is that the molecule does not simply remain as a filler,” Prof. Henke continues. “It enters into a reaction. So we are altering the chemistry at precisely the moment when the material is still liquid.”
How a Single Molecule Restructures Glass
The researchers added phenanthroline to their starting materials before heating them. Once the mixture begins to melt, the molecule does more than simply lower the temperature required for melting. It actively participates in chemical reactions that reorganize the glass network.
The process changes the immediate surroundings of metal atoms by modifying their connections to neighboring molecules.
“As a flux, the substance lowers the temperature at which the material melts; as a chemical agent, the molecule binds directly to the metal atoms and partially displaces old bonds. In the molten state, the molecule interferes with what is known as the coordination environment. This term describes how many neighbors surround a single atom. Because the new molecule binds more strongly to the metal centers, the number of neighbors increases,” explains Prof. Henke.
These interactions trigger a substantial rearrangement of the internal glass structure. Importantly, the researchers can control how extensively the material changes simply by adjusting the amount of phenanthroline added.
This gives scientists a practical way to tune the properties of glass during manufacturing rather than relying entirely on the chemistry of the original ingredients.
Lower Temperatures Prevent Damage to Glass
Another major advantage of the discovery is that it overcomes a longstanding problem in manufacturing specialized glasses.
Some of the materials investigated are unable to withstand the temperatures normally required to melt them. Instead of becoming usable glass, they begin to break down, damaging their structure and producing unwanted impurities.
The new molecular approach avoids much of this problem by allowing the materials to melt under gentler conditions.
“Thanks to this molecular trick, the material melts at significantly lower temperatures and remains stable. Studies on cobalt-containing glasses have shown that this gentler process prevents the formation of harmful decomposition products,” explains Prof. Dr. Matthias Bauer from Paderborn University.
Preventing these unwanted byproducts is particularly important when studying magnetic properties. Impurities can interfere with measurements and conceal the material’s actual magnetic behavior. By keeping the glass chemically stable, the researchers can observe these effects more clearly.
Advanced X-ray Measurements Confirm the Changes
To verify that the molecular treatment genuinely altered the glass, the research team turned to sophisticated analytical techniques.
Studying glass presents a challenge because its atoms do not follow the regular, repeating arrangement found in crystalline materials. This limits what conventional X-ray methods can reveal about its internal structure.
Prof. Bauer explains: “Instead, we used X-ray absorption spectroscopy, amongst other techniques. This method enabled us to investigate the immediate surroundings of the cobalt atoms.”
The measurements provided strong evidence that the new molecule changes the arrangement of atoms around the metal centers.
Although the cobalt atoms maintained the same chemical state (oxidation state), their local surroundings changed considerably. The bonds connecting them to nearby molecules were reorganized to accommodate the added phenanthroline.
These observations confirmed that the method does more than simply help the material melt. It changes the underlying chemistry of the glass itself.
A New Generation of Glass With Tunable Properties
The researchers also demonstrated that their approach works beyond the original materials they investigated. Successful experiments with carboxylate-based framework structures suggest that the technique could be applied to a broader range of glass materials.
This versatility is especially promising because it transforms the melting stage of production into an opportunity to design new material properties.
Prof. Henke summarizes the significance for the future: “The melt is no longer a rigid intermediate state. It becomes a reaction space in which we can program the structure.”
The ability to precisely modify metal centers could eventually lead to advanced glass components designed for specific technological purposes.
Potential applications include chemical catalysts, sensors, and optoelectronic devices that use interactions between light and electricity. Researchers could also develop materials capable of controlling magnetic behavior, manipulating light, or influencing chemical reactions with greater precision.
By turning molten glass into a material whose chemistry can be deliberately adjusted, the discovery offers a new route toward specialized glasses with properties that conventional manufacturing techniques could not easily produce.
Source: www.sciencedaily.com
