Mixture experimental design applied to gallium-rich GaO3/2-GeO2-NaO1/2 glasses

A mixture-design method was used as a multivariate data analysis tool to investigate properties of gallate glasses in the GaO3/2-GeO2-NaO1/2 system. The objective was to design compositions having gallium oxide as the main component of the glass expected for further applications like wave guided transmission in the near- and mid-infrared optical domain. Accordingly to this tool a set of glass compositions were defined in a constrained domain of the ternary glass system rich in gallium oxide and prepared by the traditional melt-quenching technique. Sample density, refractive index, multiphonon cut-off wavelength as well as thermal characteristics were measured as representative multiple responses and a linear model fitting those physical properties vs glass composition was established. The obtained model allows to predict and optimize the different responses for any composition in the studied domain and a better understanding of the influence of each glass component on its physical properties. This study demonstrates that gallium-richest compositions lead to an increase in the polarizability and contribute to a slight enlargement of the transmission window which are the primary conditions requested for intended applications. Complementary structural investigation allows to confirm the influence of the component content in the glass composition revealed by the model.