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

In order to explore IR transmitting materials and host materials for rare earth doped amplifiers, Chalcohalide glasses of three systems, GeS2-Ga2S3-CsCl, GeS2-Ga2S3-AgI and As2S3-Pbl2, were studied, respectively. The formation, short-range structure, optical and thermal properties of these three system glasses were investigated systematically by XRD, DTA-TG analysis, FTIR&UV-Vis spectra and Raman scattering studies, et al.GeS2-Ga2S3-CsCl glasses have excellent glass-forming abilities. Most glasses show strong thermal stabilities against crystallization. The glass transition temperatures, Tg, are within 175~375 C. Increasing the CsCl content at a constant ratio of GeS2/Ga2S3=4, Tg decrease first and then increase slightly, finally decrease continuously. However, the densities increase first and decrease subsequently, and the values are about 2.82 ~ 3.05g/cm3. The IR cut-off wavelengths are around 12.8 m due to the Ge-O impurities, the transmittance is up to 80%. The short-wavelength absorption edge shifts from 453nm towards ultraviolet region to 410nm with increasing CsCl content, the transmittance in visible region also increases in the same sequence. Raman results demonstrate that CsCl break the metal-metal bonds of S3Ga-GaS3 and edge-shared GaS4/2 tetrahedral to form Cl-Ga bonds, and produce complex anions [Ga2S2S2/2Cl2] 2-. GeS2 is the network former, Ga2S3 is the network intermediate, and Cs+ ions may surround [Ga2S2S2/2Cl2]2- acting as charge compensators.GeS2-Ga2S3-AgI system has a relatively narrow glass-forming region which extends from the GeS2-rich apex down to the sample containing 40% GeS2. Bulk glasses can be obtained when the content of Agl is less than 33%. Tg range from 170 to 353 C. Tg and Tx decrease almost linearly with increasing Agl content when AgI/Ga2S3=2, while the densities increase linearly with the values between 2.84~3.93g/cm3. At the same time, the T and H also decrease. Glasses show excellent chemical stability. The IR cut-off wavelengths of glasses are as long as 11.04 m, and it corresponds to the multiphonon absorption of Ge-S and Ga-S bonds. The addition of AgI doesn't change the short-range structure of glassnetwork, the basic structural units forming the backbone of the network are GeS4/2 and GaS4/2 tetrahedral which are interconnected by bridging sulfurs to form a disordered three-dimensional network, Agl disperse in it as network modifier.The maximum molar ratio of Pb^ in As2S3-Pbl2 binary glass is 25% when quenched in the icy water. And they show good chemical stability in normal air conditions. The glass transition temperatures are within 194~201 'C, and they decrease with the increasing PbI2 content. [AsS3/2] pyramids are interconnected via sulfur bridges to form disordered network. Octahedral [PbI6] works as network modifier and they are homogeneously dispersed in the disordered network by linking with [AsS3/2] pyramids by S-I bonds.Systematical studies on these three glass systems indicate that they are all promising candidates for IR optical fiber materials. And GeS2-Ga2S3-CsCl glasses are potential host glasses for RE doped 1.3 m amplifiers.