Calculation of glass properties
（重定向自Additivity principle）
![The calculation of glass properties allows](/Images/godic/202412/18/Spidergraph_Refractive_Index1815.GIF")
![The mixed-alkali effect: If a glass contains more than one alkali oxide, some properties show non-additive behavior. The image shows, that the viscosity of a glass is significantly decreased.[11]](/Images/godic/202412/18/Mixed-Alkali_Effect_Viscosity1815.GIF")
![Decreasing accuracy of modern glass literature data for the density at 20 °C in the binary system SiO2-Na2O.[12]](/Images/godic/202412/18/Measurement_Error_Development1815.gif")
![Refractive index in the system SiO2-Na2O. Dummy variables can be used to quantify systematic differences of whole dataseries from one investigator.[12]](/Images/godic/202412/18/Refractive_index_SiO2_Na2O1815.gif")
The calculation of glass properties (glass modeling) is used to predict glass properties of interest or glass behavior under certain conditions (e.g., during production) without experimental investigation, based on past data and experience, with the intention to save time, material, financial, and environmental resources, or to gain scientific insight. It was first practised at the end of the 19th century by A. Winkelmann and O. Schott. The combination of several glass models together with other relevant functions can be used for optimization and six sigma procedures. In the form of statistical analysis glass modeling can aid with accreditation of new data, experimental procedures, and measurement institutions (glass laboratories).