Effect of crystallization degree on optical characteristics of NB2O5 by sol–gel process

In this study, Nb 2 O 5 was prepared by the sol–gel method. Crystallization process was investigated by thermal analysis (TG–DSC), X-ray diffraction (XRD), UV–vis spectra and Raman spectra. TG–DSC results indicated that amorphous Nb 2 O 5 appeared at 460[Formula: see text]C. XRD results indicated that amorphous Nb 2 O 5 transformed into pseudo-hexagonal phase and crystallization degree has an increasing trend with an increase of temperature. UV–vis and Raman spectra results reflected the significant variations of optical property and atomic structure in this process. Nb 2 O 5 atomic arrangement transforms from short-range order to medium-range order, then to long-range order. Atoms transform into long-range ordered structure through connection of structural units with increasing temperature. Additionally, crystallization degree, optical property and atomic arrangement all are mutually connected in the crystallization process.