Structural studies of lithium triborate (LBO-LiB_3O_5) in borophosphate glass-ceramics

摘要

In this paper lithium borophosphate glasses and glass-ceramics in the system 0.75|xB_2O_3.(100-x)P_2O_5|.25Li_2O.yFe_2O_3 with 0 ≤ x ≤ 100 mol.% and y = 4 mol.%, were studied by X-ray powder diffraction, Mossbauer and infrared spectroscopy. All the samples in the system present a glass or glass-ceramic behavior which was confirmed by X-ray diffraction. From our Mossbauer analysis, high spin Fe~(2+) and Fe~(3+) in a distorted octahedral coordination are present in all samples. One can conclude that both iron ions are at sites of distorted octahedral coordination, acting as network modifiers (NWM) in a very broad site distribution, which is characteristic of an amorphous structural neighborhood. Such glasses and glass-ceramics containing nonlinear optical materials formed in a controlled crystallization process would be interesting candidates for applications in new nonlinear optical devices.