Sol‐Gel Processing of Neodymia–Silica Glass

Abstract

Neodymia-doped glasses are currently commercially available for use in laser systems. 'Qpically, these glasses are low-softening-temperature borates, phosphates, silicates, and fluorides. With its high softening temperature, high thermal shock resistance, and low nonlinear index of refraction, silica may be an ideal candidate for a neodymia host glass for high-power laser applications. Conventional glass processing methods, however, have thus far succeeded in incorporating only low levels of neodymia in silica. In this paper, the fabrication of neodymia-silica glasses with high neodymia content by the sol-gel route is described. A possible structure for neodymia in silica is discussed.

Inorganic and organically modified rare-earth-doped silica gels

“…Since the fluorescence line-narrowing spectra indicate that appreciable clustering is present, the longer lifetimes indicate that the use of fluorinated Eu3+ precursors leads to lower hydroxyl content in the densified gels. These findings indicate that the in-situ dehydroxylation effect observed previously upon HF addition (Pope and Mackenzie, 1993) or postdensification fluorination (Rabinovich et al, 1986) can be achieved by directly incorporating fluorine into the rare-earth precursor.…”

“…The use of organically modified silicon alkoxide sol-gel precursors (Capozzi and Seddon, 1994) and the addition of fluorine as a dehydroxylating agent (Pope and Mackenzie, 1993) have been demonstrated to reduce the hydroxyl content in silica-gel glasses. Organically modified precursors contain hydrophobic alkyl groups that act to inhibit water and hydroxyl retention (Zhang et al, 1995), while the presence of fluorine induces chemical reactions upon heat treatment that act to remove water and hydroxyl groups from sol-gel silica (Rabinovich et al, 1986).…”

Sol-gel synthesis of fluorine-doped silica glasses with low SiOH concentrations

“…17 20) and SiF 4 , 20) may also be used as fluorine sources and dehydrating agents. However, probably because the elimination of SiOH groups by the liquidphase fluorine doping alone was often insufficient, postdehydration during sintering using halogen-containing gases 7) or vacuum sintering 21), 22) has been commonly employed. It is also unclear how liquid-phase fluorine doping can reduce the concentration of SiOH groups in solgel derived silica glasses, although samples whose SiOH concentrations are as low as 4 ppmw have been prepared by oxygen sintering of fluorinemodified gels.…”

Influence of Temperature and Time on Nd2O3-SiO2Composite Prepared by the Solgel Process

“…In the present article, solgel technique is being used for the preparation of Nd 2 O 3 nanocrystallites in a silica matrix. Silica has been used as a host matrix due to its high softening temperatures, high thermal shock resistance, and low index of refraction [17][18][19].…”