Structural study of PbO–MoO3–P2O5 glasses by Raman and NMR spectroscopy

Efficient Energy Transfer and Enhanced Near‐IR Emission in Cu+/Nd3+‐Activated Aluminophosphate Glass

“…These basic tetrahedral units are commonly revealed in 31 P NMR spectra with a Q 3 → Q 1 shift downfield, that is, with a trend in chemical shift as Q 1 > Q 2 > Q 3 . For plain phosphate glasses, well‐defined peaks in association with the different Q n species are expected in the 31 P NMR spectra . For instance, for a pure phosphate matrix with a 50P 2 O 5 :50BaO (mol%) composition, a main peak at about −24.1 ppm with a second peak of lower intensity around −9.1 ppm have been observed by our group in association to Q 2 and Q 1 species, respectively.…”

Structural studies of AgPO3–MoO3 glasses using solid state NMR and vibrational spectroscopies

“…For AgPO 3 glass the results are in agreement with literature values [25,26]. In analogy to the situation in similar glass systems studied previously [5,[10][11][12][13], addition of MoO 3 to the metaphosphate glass results in a significant increase in T g . In addition, the DSC data indicate a remarkable increase in the thermal stability, with no crystallization exotherm being observed for samples with 0.1 ≤ x ≤ 0.3.…”

“…This structural model can also rationalize the strong increase in T g values with increasing MoO 3 content, as the interaction of MoO 3 with the polyphosphate chains results in significant crosslinking effects and an increased number of bridging oxygen atoms per network former species. The new structural model developed here is most likely also applicable other MoO 3 and WO 3 -containing metaphosphate glasses previously examined by us [5,10,11] and others [12,13] in the literature. Table 3 Deconvolution of the 31 P MAS spectra of the glasses under study: chemical shifts δ (± 0.5 ppm), full widths at half maximum Δ (± 0.5 ppm), and fractional areas (± 2%).…”

“…In the following, these environments will be categorized in terms of the Q (n) mMo terminology, where n represents the number of P-O-P linkages, while m denotes the number of molybdenum species linked to the phosphate group (m + n ≤ 4). This notation differs from the one used by us in our previous publications [5,10,11] (where n denotes the number of bridging oxygen atoms rather than the number of P-O-P linkages), but is consistent with the one used by Koudelka et al [12,13]. Based on the evidence from Raman spectroscopy and 95 Mo NMR, we proceed on the assumption that the molybdenum local environment is the same as that in AgMoO 2 PO 4 (i.e.…”

“…Incorporation of MoO 3 or WO 3 into alkali metaphosphate glasses is known to result in dramatically increased glass transition temperatures, suggesting that the glass structure is affected by strong mixed-network former effects [5,10,11]. These have been previously examined, using Raman scattering and various complementary single and double resonance solid state NMR techniques in various metaphosphate glasses containing either metal oxide [5,[10][11][12][13]. As previous publications on related systems have shown that the informational content of 31 P MAS-NMR spectroscopy is somewhat limited by intrinsically poor spectroscopic resolution, the present contribution introduces two new experimental approaches to these glass systems.…”