Characterization of the disordered phosphate network in CaO–P2O5 glasses by 31P solid-state NMR and Raman spectroscopies

31P NMR characterisation of phosphate fragments during dissolution of calcium sodium phosphate glasses

“…The actual signal position is not only dependent on the type of Q n group and (particularly in the solid glass) of the type of modier connected to it, but it also depends on the neighbouring groups (e.g. Q 1 or Q 2 ), 32 and it is known that structural groups present in rings give a different chemical shi to the same group not present in rings. 33 While (solid-state) 13 P MAS NMR cannot resolve these differences easily, 34 solution 31 P NMR can, and we thus conclude that the large number of peaks observed in 31 P MAS NMR spectrum (dashed black curve) together with the result of a deconvolution (red curve) into three Gaussian lines (lower red curves) at +1.1 ppm (12% of total signal), À7.6 ppm (64%) and À21.2 ppm (24%).…”

Structural, UV-VIS-NIR Luminescence And Decay Associated Spectral Profiles Of Sm3+ Doped Calcium Phosphate Glass

“…This is the result of the delocalization of bonds in Q 3 tetrahedra, from the P=O terminal oxygen bond to the bridging P-O-P oxygen bonds [24]. The bond at around 1170-1180cm -1 is also characteristic of the alkali oxides added to P 2 O 5 glasses, and it increases with the oxide content [23][24][25].…”

“…It is possible to observe the presence of three main regions; in the range 600 -900 cm -1 , 1100 -1300 cm -1 and 1500 -1800 cm -1 . These regions can be assigned, respectively, to the vibrations of P-O-P bonds, symmetric vibration of the middle chain (PO 2 )and vibrations of the P-O double bond [23]. In pure P 2 O 5 glasses, there are two main bands at 1390 cm -1 and 640 cm -1 .…”

Thermodynamic model and Raman spectra of CaO–P2O5 glasses

“…The role and importance of binary calcium phosphate glasses can be found mainly in the field of fundamental study of composition-structure-property relationships [1][2][3][4]. On the other hand, the high UV transmittance can be mentioned as a technologically significant aspect.…”

“…The aim of the study was the validation of the thermodynamic model of Shakhmatkin and Vedishcheva [8][9][10][11][12][13][14] by its application in the spectral decomposition by the method of Malfait. In our previous work [15], the Shakhmatkin and Vedishcheva model was successfully used for reproducing the Q-distribution in CaO-P 2 O 5 glasses measured by 31 P MAS NMR [4]. Despite the more sophisticated and more complex thermodynamic models were used for study of phosphate glass-forming melts, e.g., the two sublattice model [5], the Shakhmatkin and Vedishcheva model is appealing for its simplicity and the fact that it does not contain any adjustable parameters.…”