The invention relates to a glass sheet bearing a multilayer stack comprising at least one functional layer which is based on a material that reflects infrared radiation and at least two dielectric coatings, such that each functional layer is surrounded by dielectric coatings. According to the invention, the dielectric coatings include at least one layer that is based on a mixed zinc/tin oxide containing at least 20 % tin and at least one oxygen diffusion barrier layer with a thickness of more than 5 nm. The inventive glass sheet can form the basis of glazing with high thermal insulation, which is very useful, for example, in the building and automotive industries.