Crystallization of niobium germanosilicate glasses

Crystallization and Second Harmonic Generation of Lithium Niobium Silicate Glass Ceramics

“…This value is high for silicate glasses and exceeds by ∼1 order of magnitude one of the highest I max reported for silicate glasses, determined for 2Na 2 O–CaO–3SiO 2 glass composition ( I max ∼4.3 × 10 13 m 3 /s) 34 . Only few glass compositions, like 2BaO·TiO 2 ·2SiO 2 and niobium germanosilicate glasses, present higher nucleation rate, with 10 17 and 9.7 × 10 18 m 3 /s, respectively 29,35 …”

“…by density measurements, according to the following equation: where ρ sample is the density of the LNS glass 35Li 2 O–25Nb 2 O 5 –40SiO 2 heat treated at the temperature of maximum nucleation for 2 h, ρ glass is the density of the untreated glass sample and ρ crystal is the experimental density measured on LiNbO 3 crystal 27 . The crystallized volume fraction was determined to estimate the nucleation rate, I , which can be obtained thought the expression proposed by James and colleagues in the case of homogeneous nucleation 28,29 : where t HT is the heat‐treatment duration and N v (t) is the number of crystals per unit volume after time t . N v (t) can be evaluated by dividing the crystal volume fraction by the average volume of one particle.…”

High niobium oxide content in germanate glasses: Thermal, structural, and optical properties

“…These behavior suggests that the crystallization mechanism occurs preferably in the volume (bulk), which is in agreement with the data obtained by the isothermal method. Bulk crystallization has also been identified for germanosilicates glasses containing niobium . This mechanism is promising since the distribution of the nanocrystals in the glass bulk is important for obtaining glass‐ceramics with good optical quality.…”

Optical and spectroscopic properties of germanotellurite glasses

“…c) Glass-forming region of the germanotellurite system, for a cooling rate of~100°C/s. The squares represent glass forming compositions found in the literature[1,8,[20][21][22][23][24].…”