Liquids that are cooled sufficiently slowly undergo a first order transition at their melting temperature as they crystallize into a periodic, ordered structure. However, if cooled rapidly, the crystallization process can be avoided, and the supercooled phase entered instead. Some materials' viscosity exhibits an extremely dramatic dependence on temperature when in the supercooled phase - it can grow by several orders of magnitude upon a reduction of a mere few percent in temperature. The relative sensitivity of the viscosity of supercooled liquids to temperature variations is commonly known as "fragility"; the stronger the dependence of the viscosity on temperature, the more fragile a supercooled liquid is said to be.

The phenomenon of fragility presents one of the most mysterious unsurmounted challanges of theoretical condensed matter physics for decades now. In my research I study simple model glass formers, in an effort to identify relations between various characteristics of the microscopic structure, and the huge slowing-down of the dynamics seen in the supercooled liquid phase.