Structural studies of lead aluminate glasses

Raman and 27Al NMR structure investigations of aluminate glasses: (1−x)Al2O3−x MO, with M=Ca, Sr, Ba and 0.5<x<0.75)

“…Moreover, the values of δ iso decrease with increasing the size and weight of cation substitution. This result is in good agreement with those observed for lead aluminate [45] where the δ iso of [4] Al decrease from 76 and 72 ppm when PbO content decreases from 75 to 72 mole % of PbO . The absolute values of δ iso are lower in PbO-Al 2 O 3 system than those observed for Ba which confirms that the 27 Al chemical shift is very sensitive to the nature (weight and size) of the second neighbour element Pb, Ba, Sr or Ca in the aluminate.…”

A neutron diffraction and 205Tl NMR study of the thallium germanate glass system

“…The value for n Tl-O in Table 3 is significantly less than three, and this probably indicates that thallium is present as both modifier and glass former. This mix of environments has also been observed in other lone pair glass systems containing either lead or tin [20,21,27,49]. At longer distances the correlation functions for the two samples are very different as the presence of thallium acting as a glass former significantly alters the glass structure.…”

“…On the other hand, two different X-ray diffraction studies [12,53], and a combined X-ray diffraction, neutron diffraction and 29 Si NMR study [13], have all found evidence that Pb may be on asymmetric PbO 3 sites for all lead silicate compositions. Diffraction studies of other lead containing glasses give similarly mixed results: An X-ray diffraction and 11 B MAS NMR study of lead borate glasses [16] has shown that the Pb-O coordination number is about 6 for low PbO content, falling to about 3 for high PbO content, and a study of lead aluminates indicates that high coordination Pb sites exist in glasses containing less than 70 mol% PbO [20,21]. However, contrastingly, a neutron diffraction study of lead gallate glasses showed no evidence of Pb in high coordination number, modifier sites [18,19].…”

“…Several optical studies have shown that glasses containing Tl 2 O give some of the highest non-linear optical responses measured in heavy-metal oxide glasses [4,5]. However, although many diffraction studies of glasses containing lone pair ions have been carried out, predominantly for tellurite and lead containing systems [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], almost none have been published on binary glasses containing thallium.…”

Solid-State Lithium Ion Electrolytes

“…Glass-forming regions are normally reported in 2D and 3D ceramic phase diagrams. Glass-forming regions could be expanded by fast-quenching (up to 10 6 K/s) obtained by means of roller-quenchers [38]. During '90s sol-gel recipes were increasingly used to prepare silicate and later borate glasses [39].…”