Filling Material and Characteristic of Polymer-Impregnated Turquoise in Anhui Province

Features of different kinds of organic polymer filling materials and corresponding organic polymer-impregnated turquoise samples were tested with the help of Fourier transform infrared spectroscopy, laser Raman spectroscopy and UV-Vis spectrophotometer. The spectral characteristics could be a reference to the identification of these organic polymer-impregnated turquoise.The vibrational peaks of —CH₃ at 2 978 cm^-1, —CH₂ at 2 930 cm^-1, C=O bands at 1 722 cm^-1 and COC bands at 1 256 cm^-1 are common in the infrared spectrum of liquid glue samples. In the infrared spectra of curing agent, the vibration peak at 1 715 cm^-1 is attributed to the stretching vibration of C=O and the vibration peaks at 1 418, 1 327 cm^-1 are attributed to the bending vibration of COO. The infrared vibration peaks of the main group of the cured glue samples were the same as the liquid glue samples. The vibration peaks of the organic polymer-impregnated filled turquoise in the infrared spectrum appeared in 2 920-2 940, 1 720-1 730, 1 390-1 470 cm^-1 or 1 220-1 300 cm^-1. Raman spectrum showed high fluorescence background. However, different vibration peaks in 2 890-2 990 cm^-1 could be evidence to identify organic polymer-impregrated turquoise. In the UV-Vis absorption spectra of organic polymer-impregnated turquoise, absorption band caused by Fe³⁺ appeared at 432 nm and absorption band caused by Cu(H₂O)₄ ²⁺ appeared at 600 nm, which was consistent with the characteristics of the untreated turquoise. UV-Vis spectra of dyed turquoise also showed absorption bands at 475 nm and 515 nm.