Abstract
A model glass is studied by classical molecular dynamics and the Voronoï cells are determined at various times and temperatures. All their characteristics of physical interest are studied as a function of temperature. In particular, as temperature increases in the glass phase, the fraction of 4- and 6-edged faces (encircling disclination defect lines) increases at the cost of 5-edged faces. At the glass transition this trend is reversed and a majority of pentagons is recovered in the liquid phase. These results shed new light on the evolution of the local structure through the glass transition.