Modeling the thermal poling of glasses using molecular dynamics. Part 1: Effects on glass structure

Due to its ability to permanently alter key properties of glasses after melting, thermal poling is considered a promising candidate for post-melt processing of glasses. However, in order to take full advantage of this technique, a deeper understanding of the processes involved in the compositional and structural changes observed after poling is necessary. In this study, we evaluate the advantages and limitations of using Molecular Dynamics (MD) to study thermal poling. We show that MD can successfully reproduce key experimental observations related to thermal poling. Specifically, the conversion of B^IV to B^III in borosilicates with four different network modifiers is well replicated in our simulations. Moreover, our simulations reveal the coordination number of Al atoms is redistributed between the IV, V and VI coordination states. The elimination of non-bridging oxygen is also observed after poling in more than 80 oxide glasses including aluminosilicates and borosilicates. Overall, our study shows that MD can be a highly effective tool to gain valuable insights into the significant structural rearrangements that occur in glass networks during thermal poling.