Fluoride phosphate glasses

Ledig M, Heumann E, Ehrt D, Seeber W (1990) Spectroscopic and laser properties of Cr ", Yb ", Er " fluoride phosphate-glass. Opt Quant Electron 22 S107-S122... 

F A1 and A1 " F REDOR experiments and " F A1 TRAPDOR and REAPDOR experiments provided information on spatial proximities between F and A1 in many Al-based fluorides. We can cite aluminium fluoride phosphate glasses [40,41], aluminosilicate glasses [42] and zeolites dealuminated with NH4SiF6 [43,44]. Other examples are detailed in Section 5.3. 

L. Zhang, C. C. de Araujo, H. Eckert, A new sol-gel route to aluminum fluoride phosphate glasses mechanistic investigations hy NMR spectroscopy, Chem. Mater., 17, 3101-3107 (2005). 

Also the UV-light induced photoreduction in doped phosphate and fluoride-phosphate glasses [359] and the phase separation in highly tin-doped fibres and preforms during UV-eposure [63] were investigated. 

Seeber W, Ehrt D, Ebendorffheidepriem H (1994) Spectroscopic and laser properties of Ce " -Cr -Nd co-doped fluoride phosphate and phosphate-glasses. J Non-Cryst Solids 171 94-104... 

Some zinc phosphate glasses have low transition temperatures and excellent water resistance [19], Fluorophosphate glasses based on AlfPOjlj and LiF possess special optical properties in addition to having good water resistance. Glasses of this kind, based on combinations of other cation metaphosphates and fluorides, have been patented [20]. 

Within a few years these very first results were followed by laser effects in other R ions such as Pr +, Ho +, Er +, Tm +, Yb +, Dy +. In particular Er laser emission at 1.5 pm was obtained in silica glass (Snitzer and Woodcock 1965), and studied in phosphate, beryllium fluoride, fluorophosphate glasses (Auzel 1966a, 1968). All these pioneer results have already been reviewed in several books (for instance, Di Bartolo 1968, Roess 1969, Weber 1979 in volume 4 of this Handbook Kaminskii 1981, Reisfeld and Jorgensen 1977). 

ZBLA zirconium barium fluoride glass LLP lithium lanthanum phosphate glass ZT zinc tellurite glass. 

The movement of fluoride through the atmosphere and into a food chain illustrates an air-water interaction at the local scale (<100 km) (3). Industrial sources of fluoride include phosphate fertilizer, aluminum, and glass manufacturing plants. Domestic livestock in the vicinity of substantial fluoride sources are exposed to fluoride by ingestion of forage crops. Fluoride released into the air by industry is deposited and accumulated in vegetation. Its concentration is sufficient to cause damage to the teeth and bone structure of the animals that consume the crops. 

The progress of precipitation is revealed by the concentration/time curves for zinc and phosphate, since both these species are present initially in solution. There should be maxima for the soluble aluminium, calcium and fluoride which are extracted from the glass, but because of the early onset of precipitation these are not observed. Precipitation is accompanied by an increase in pH when it reaches 1-8, at which juncture 50% of both zinc and phosphate have been precipitated, the cement paste gels (5 minutes after preparation). 

The composition of the leachates does not correspond to the composition of the cement at all (Wilson Batchelor, 1967a,b). The predominant species eluted are the soluble sodium salts of phosphate and fluorides, although sodium is only a minor constituent of the cement. For one example of cement examined, the leachate contained 0-28 % sodium and 0-20% phosphate (expressed as a percentage of the amount of the species contained in the cement). For the major constituents of the glass the figures were 0 07% fluoride, 0 02% Al Oj, 0 01 % SiOj and 0 003% CaO. 

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