Effect of heat treatment on the infrared absorption spectra of strontium-sodium-borosilicate glass

Abstract

<span style="font-size:12.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">Infrared absorption spectra of the prepared strontium-sodium-borosilicate glass (SiO₂ 80%-Na₂O 12.5%-B₂O₃ 5%-SrO 2.5%) are studied in the frequency range 200-4000 cm^-1, where strontium oxide was introduced on partial replacement of soda in sodium-borosilicate glass, to show the effect of divalent metal oxide introduced on the structural units SiO₄, BO₄, and BO₃ within the network structure of strontium-sodium-borosilicate glass, in the temperature range 27-800°C. The deformation of SiO₄ tetrahedra is investigated by using the baseline method, the temperature dependence of the relative integrated intensity, the relaxation time, and rotational energy barrier of this glass proved that the glassy phase is transformed to crystalline phase at 500°C. A slight shift occurs in the strongest bands of SiO₄ tetrahedra to higher frequencies, with temperature increase, which indicates an increase in the force constants between the components of the glass network structure. The increase of the absorbance in the temperature range 600-800°C indicates strengthening of the SiO₄ bonds.</span>