How shock waves change glass

Silica glass used in lasers, fiber-optic cables or other high-technology applications is often exposed to extremes of temperature or pressure, which can cause structural changes in the glass. Understanding these changes is important for selecting the right materials for building different kinds of devices.

Simulations of glasses by UC Davis graduate student Lilian Davila show how pressure waves like those caused by a pulse of laser light change the atomic structure of glass, making it denser and less brittle.

Atoms of silicon and oxygen in silica glass are arranged in rings of three to 10 atoms. After a compression wave, the proportion of smaller (three or four atoms) and larger (nine atoms) rings increases and fewer intermediate-size rings are found, Davila found.

Further calculations predict how tiny structural defects could affect the optical properties of glass.

The work, which was published in the journal Physical Review Letters, was supervised by Subhash Risbud and James Shackelford, both professors of chemical engineering and materials science at UC Davis, in collaboration with Maria-José Caturla, Alison Kubota, Babak Sadigh and Tomás Díaz de la Rubia at the Lawrence Livermore National Laboratory and Stephen H. Garofalini at Rutgers University, New Jersey.

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