INFLUENCE OF B2O3 ON THE INTERACTION IN THE SiO–GeO2 SYSTEM

Abstract

The influence of the B2O3 additive on the nature of the interaction in the SiO–GeO2 system was investigated by X-ray diffraction and IR transmission spectroscopy. The nature of the diffractograms of the SiO–GeO2–B2O3 system with a composition of 1:1:0.5 and 1:1:1 corresponds to the presence of SiO2 phases of hexagonal modification (quartz) and GeO2 of various modifications, as well as, possibly, a crystalline B2O3 phase. The exact value of the content of the reaction products and initial components could not be determined due to the significant content of the X-ray amorphous component of unknown composition. The broadening of the diffraction peaks and the presence of a distinct halo testify to the benefit of the processes of nanostructuring and glass formation. However, the absence of elemental germanium in the SiO–GeO2–B2O3 system, in contrast to the SiO–GeO2 system, was clearly established. The nature of the IR transmission spectra of samples with different content of B2O3 additive differ significantly from each other. Thus, the IR transmission spectra of the sample with a composition of 1:1:0.5 contain weak absorption bands due to the oscillations of the B–O bonds; instead, they reveal periodic oscillations characteristic of nanostructured systems. In the spectra of the sample with a composition of 1:1:1, the absorption bands due to the oscillations of the B–O bonds are very distinct, but there are no oscillations. Therefore, the addition of B2O3 probably accelerates the formation of Germanium monoxide, which in turn reacts with the B2O3 additive and possibly with SiO2 as one of the reaction products. Testing of samples of the SiO–GeO2–B2O3 system by the method of thermal evaporation in a vacuum revealed the advantages of the sample with a composition of 1:1:1 in the ability to form a strong and durable coating. It was possible to determine the refractive index for it, which is 1.93 at a wavelength of 1000 nm. Instead, the coating obtained from the 1:1:0.5 composition sample turned out to be unstable. A conclusion was made about the need for further optimization of the composition and synthesis conditions to obtain materials with the required parameters.