The LIMES project (Light Innovative Materials for Enhanced Solar Efficiency), a Solar-ERA.NET project, was a fruitful collaboration to optimize many different properties in state-of-the-art solar glasses for photovoltaic (PV) modules. Here, we present results related to the effectiveness of combining chemical vapor deposition and thermal strengthening of glass in a simultaneous process. The treated glass surfaces gets a markedly increase of Al₂O₃, which in previous studies has been shown to have a beneficial effect on the mechanical properties. Successful thermal strengthening and in-situ Chemical Vapor Deposition (CVD) have repeatedly been performed on 4 and 2 mm flat glasses. The strengthening level has been quantified using SCALP (Scattered Light Polariscope). The samples were found to have a surface compressive stress in the range of 85-110 MPa which is comparable to the level of conventional thermally strengthened safety glass. The surface mechanical properties of the samples have been investigated by means of nano/microindentation and the strength of glasses has been quantified by ring-on-ring method. The transparency of the samples after washing was characterized by UV-Vis spectroscopy.

The in-situ CVD thermally strengthened glasses gets an Al₂O₃ coated surface which exhibits increased crack resistance and increased scratch resistance as compared to traditionally thermally strengthened glass. The nanohardness for low loads, ≤ 1 mN, follow the order thermo-chemically strengthened glass > thermally strengthened glass > annealed float glass. The results of the strength tests show that the 2 mm thin glass were positively affected by the Al₂O₃ coating while the 4 mm did not show any significant change. The light transmittance of the treated glasses was not markedly reduced. In summary, this novel process show possibilities to increase specific properties, in this case surface mechanical properties, by simultaneous CVD and thermal strengthening.