Synopsis: Amber Does Not Act Its Age

110-million-year-old amber samples surprisingly retain the same thermodynamic properties as much younger amorphous solids.

Amber is a vitrified resin valued for its beauty and the intriguing specimens occasionally trapped within it. Now, scientists are studying ancient amber samples to determine how their glasslike properties change with time. Amber is a unique example of a glass because it has “hyperaged,” i.e., has undergone thermodynamic stabilization for millions of years—a process that is impossible to replicate in a lab.

Conventional, nonhyperaged glasses characteristically exhibit a so-called boson peak—an enhancement in the density of vibrational states over that expected for a crystalline solid. As reported in Physical Review Letters, Miguel Ramos at the Autonomous University of Madrid, Spain, and his collaborators used 110-million-year-old Spanish amber samples to investigate how the boson peak changes as the amber samples are subjected to thermal annealing, which effectively de-ages them. Previous studies suggested that the strength of the boson peak diminished with annealing, although the samples that were tested had only cooled for moderately short laboratory time scales.

Ramos and his team measured the specific heat of several amber samples, comparing specimens of pristine hyperaged amber, samples that had been annealed at temperatures below and around their glass transition temperature, and “rejuvenated” amber that had been heated well above its glass transition temperature. The annealed samples represented glasses with partially erased thermal histories, while the rejuvenated amber had had its 110-million-year cooling cycle effectively erased. The authors found that the specific heats of all the samples were identical within the experimental errors for temperatures below 1 kelvin. This finding implies that the boson peak and other thermodynamic properties remain fossilized in the glass—much like a trapped insect—and are unchanged by more than 100 million years of aging. – Katherine Kornei


Features

More Features »

Announcements

More Announcements »

Subject Areas

Materials Science

Previous Synopsis

Next Synopsis

Related Articles

Synopsis: Discovering New Magnetic Materials with Machine Learning
Materials Science

Synopsis: Discovering New Magnetic Materials with Machine Learning

A new computing experiment suggests that machine-learning algorithms can accelerate the discovery and design of new magnetic materials. Read More »

Synopsis: Softening Tones Make Shear-Thickening Fluids Relax
Materials Science

Synopsis: Softening Tones Make Shear-Thickening Fluids Relax

An acoustic signal can control the viscosity in shear-thickening materials, which have potential uses as impact absorbers. Read More »

Viewpoint: A Prediction for “Hot” Superconductivity
Materials Science

Viewpoint: A Prediction for “Hot” Superconductivity

A proposed hydrogen-rich solid would superconduct above the boiling point of water—though the material would need to be subjected to a colossal pressure. Read More »

More Articles