Studying how glasses react to extreme pressure helps scientists understand how their structure evolves. The research team led by Oak Ridge National Laboratory's Chris Tulk used a newly designed pressure cell to exert 15 GPa (about 2,200,000 pounds per square inch) upon a sample of germania (GeO2) glass. The researchers studied its transformation from a simple structural motif with four oxygen atoms surrounding a germanium atom to a high-density six oxygen atom motif that had never been fully characterized. The researchers used intense beams of X-rays and neutrons for diffraction, along with computer simulation of molecular motions, to study the structural changes in more detail than ever before. This class of glass includes silica (SiO2), an abundant component in the deep Earth, and was thought to undergo an abrupt transformation from low to high density forms. This study shows a more complex slow transformation a significant finding with general implications for glass chemistry. The work, which will be featured an upcoming issue of Physical Review Letters, may reveal more about the nature of matter and help seismologists learn more about the Earth's deep interior, where high pressures impact the planet's formation.
Menu