Study On The Composition, Structure And Properties Of Ge-S-based Chalcohalide Glasses For Infrared Optical Fiber Materials

Due to excellent infrared transmission, infrared optical fiber materials are becoming more and more significant in the field of sensor, power transmission and telecommunication. Owing to isotropy, homogeneity and higher transmission in visible and infrared region, chalcohalide glasses become ideal infrared optical fiber materials. This thesis studied the microstructures and some properties such as preparation techniques, glass-forming regions, thermal properties, optical properties and chemical bonds of two types of chalcohalide glasses(GeS2-Ga2S3-KCl and GeS2-In2S3-KCl). The relationship between properties and compositions was studied. Furthermore we analyzed the effect of KC1 on the properties of glasses in terms of composition-structure-property.In the GeS2-Ga2S3-KCl glasses, the content of KC1 can reach 60 mol%. The glass forming region of GeS2-Ga2S3-KCl system was the boundary extending from the glass-forming region of the quasi-binary GeS2-Ga2S3 system toward the complex structural units' MGaS3/2Cl, which shaped a long and narrow region encircling composition E.Although xGeS2-(l-x)In2S3 binary system didn't form vitreous state, we can obtain transparent glasses with the addition of KC1. Even in the composition B: 0.7GeS2-xIn2S3(1-x)KCl, the minimal mol content was 0.015. Moreover, glass colors vary conspicuously according to different compositions. The glass forming region of GeS2-In2S3-KCl system was similar to that of GeS2-Ga2S3-KCl system, which was a long and narrow region expanding from the two sides of composition In2S3/KCl=l/l. In this system the maximal mol content of KC1 exceeded 0.45.These two systems had higher temperature of the glass transition, which was between 300 and 400 C. The glass-forming ability was good and reached 0.25-0.3. Cl- destroyed a degree of glass-networkconnectivity, so the temperature of the glass transition decreased with the introduction of KC1. The relationship between the content of KC1 and glass-forming ability was non-linear: with the addition of KC1, the value of increased at first and then decreased.The ultraviolet and infrared cut-off wavelengths of these two systems were appropriately 0.45~11.5um. With the addition of KC1, infrared cut-off wavelengths almost remained constant, but the short-wave absorption edges shifted towards shorter wavelength next to the visible transmission spectra.Raman spectra showed that KC1 didn't react with GeS2- The microstructure of the investigated glasses was considered to be that the complex anions [GaS3Cl]" or [InSsCl]" formed by Ga (In)-S bonds and Ga (In)-Cl bonds were homogeneously dispersed in a disordered polymer network formed by GeS4 and GaS4 tetrahedrons interconnected by sulfur bridges.