Robson F. Muniz, Jean Bertrand Dominique De Ligny, Martinent, C, Marcelo Sandrini, Aantonio Medina Neto, Jurandir Hillman Rohling, Mauro Luciano Baesso, Sandro Marcio Lima, Luis Humberto Da Cunha Andrade, Michel Luc Yannick Guyot

JOURNAL OF PHYSICS. CONDENSED MATTER – Volume: 28, Páginas 31: , Issue: Doi: 10.1088/0953-8984/28/31/315402

In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH(-)-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ([Formula: see text][T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q (n) species to Q (n-1). In the case of Al-rich glass, the Al in the smallest Q (n) units evolved from tetrahedral to higher-coordinated Al (([5])Al and ([6])Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.