BO3 Units Research Articles

Structure and Characterization of K2Na3B2P3O13, a New Nonlinear Optical Borophosphate with One-Dimensional Chain Structure and Short Ultraviolet Cutoff Edge.

Nonlinear optical (NLO) crystals, being the primary medium for laser wavelength conversion, are crucial in all-solid-state lasers. Borophosphates offer more structural varieties than pure borates and phosphates, and they have become popular as NLO crystal candidates. Through spontaneous crystallization, we acquired a noncentrosymmetric alkali metal borophosphate crystal material, K2Na3B2P3O13 (KNBPO). KNBPO crystallizes in the orthorhombic Cmc21 space group with the following unit cell parameters: a = 13.9238(18) Å, b = 6.7673(8) Å, c = 12.1298(15) Å, and Z = 4, and its structure is characterized by a fundamental building unit 1∞ [B2P3O13] chain structure made up of bridging oxygen linkages between BO4 and PO4 tetrahedra. KNBPO has a short ultraviolet (UV) cut-off edge (<186 nm), a congruent melting characteristic, good thermal stability, and a moderate second harmonic generation response roughly 0.42 times that of KH2PO4. Theoretical calculations reveal that the optical properties of the compound mainly originate from BO4 and PO4 units. Due to the short UV cut-off edge, KNBPO can be used as a potential NLO material in the UV and even deep UV regions, and it enhances the structural variety of borophosphates, which has a reference value for scholars investigating similar materials.

Detailed optical analysis of Dy3+ and Pr3+ co-doped alumino-borate glasses for visible lighting applications

A new glass series with nominal molar composition of 60B2O3 + 30NaF + 10Al2O3 co-doped with Dy3+ and Pr3+, synthesized by melt quench was reported. The influence of Rare Earth (RE) ratio variation on prepared glasses was investigated by using Fourier Transform Infra-Red spectroscopy, UV–Vis–NIR absorption spectroscopy, Photoluminescence, Decay curves and Density measurements. Their X-Ray Diffraction and FTIR spectra revealed the glassy nature and confirmed that AlO6, AlO4, BO3 and BO4 units are the main structural units of that matrix. A non-linear variation following the same trend for tetragonal borate units (N4), Band gap, non-linear optical properties, Density, Molar Volume etc. was observed. Different optical parameters were obtained by UV–Vis–NIR spectroscopy. The Bonding parameter obtained from Nephelauxetic study indicated ionic nature of Dy3+ and covalent nature of Pr3+ ions. Photoluminescence excitation and emission spectra were recorded under variety of excitation wavelengths and corresponding color parameters were calculated using 1931 CIE standards. A detailed yellow to blue ratio analysis was reported as a function of RE ion concentration and excitation wavelengths. Composition DPNAB(x = 0.7) displayed the best performance with CIE coordinates (0.33, 0.37). Existence of Energy transfer from Dy3+ and Pr3+ was evidenced by the spectral overlap diagram and lifetime values obtained from fitting of Decay curves. From the obtained results, prepared glasses can be suggested for solid-state lighting devices like WLEDs and display devices.

Expanding gaudefroyite family to Sr2MBi(REEO)3(BO3)4 (M = Ca, Sr, Ba; REE = Y, Eu) borates with large second harmonic generation responses

The synthesis, crystal structure, and characterization of a few new noncentrosymmetric rare-earth borates of gaudefroyite family Sr2MBi(REEO)3(BO3)4 (M = Ca, Sr, Ba; REE = Y, Eu) are represented. Samples of Sr2MBi(YO)3(BO3)4 (M = Ca, Sr, Ba) borates were synthesized by multi-step solid state reactions. The crystal structures of Sr3Bi(YO)3(BO3)4, Sr2CaBi(YO)3(BO3)4 and Sr2BaBi(YO)3(BO3)4 were refined in P63 space group to R1 0.059, 0.058 and 0.018, respectively. Second-harmonic generation measured with Kurtz-Perry powder technique shows an increase in the nonlinear optical activity of materials by almost two times upon partial substitutions of Sr for Ca and Ba in the Sr3Bi(REEO)3(BO3)4 and its decrease if Y atoms are replaced by Eu. Thermal expansion coefficients for Sr2MBi(YO)3(BO3)4 (M = Ca, Sr, Ba) borates and Ca4(MnO)3(BO3)3(CO3) gaudefroyite are calculated for the first time. Thermal expansion of these compounds is almost isotropic due to the arrangement of BO3 units which are located in the ab and ac planes.

The Role of MgO Modifier on Physical, Structural, Optical andThermoluminescence Properties of Lithium Borate Glass System

Synthesis of lithium borate glass system was carried using the melt quenching technique with varying concentrations ofmagnesium followed by analysing the different characteristics such as physical, structural, optical and thermoluminesceneusing various techniques eg. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visspectroscopy, and Thermoluminescence (TL). The obtained XRD pattern confirmed the amorphous nature of the preparedsamples. Relevant physical parameters have been evaluated to study the response of these properties with respect tomagnesium content. The density and molar volume values showed that the network structure changed with increasingmagnesium content. It is evident from the FTIR spectra that the network of the prepared samples predominantly containsBO3 and BO4 units. The UV-vis spectra confirmed a decrease in the direct and indirect band gap values with increase inMgO content. Optical parameters namely refractive index, electronic polarizability, reflection loss and dielectric constantwere also calculated and found to be in good correlation with other studies. Following gamma rays irradiation with differentdoses, TL glow curves of prepared glasses were analysed. Deconvolution of TL glow curves was done using glow curveconvolution deconvolution (GCCD) function and trapping parameters of isolated peaks viz. activation energy and frequencyfactor have been determined.

Physical and optical properties of MoO3 doped B2O3-CdO-Al2O3-CaF2 glasses

The glass samples with precise composition 60B2O3-20CdO-5Al2O3-(15-x) CaF2-(x)MoO3 (where × = 0, 0.5, 1, 1.5, 2) was prepared by using standard melt quenching method. The physical and optical characteristics of the glass samples were identified by making use density and UV spectra. In the investigated compositions, the increase of non-bridging oxygen atoms, due to the conversion of Mo6+ ions to Mo5+ ions, with increased MoO3 content resulting in lowering the optical band gaps is noticed. The non-bridging oxygen levels will go up with an increase in BO4 units, improving the compositions density inturn raises refractive index and other physical parameters. Because of more density and refractive index these glass materials can have its applications in the area of radiation shielding and optical communications.

Copper doped strontium Indium-borate glasses: FTIR, Raman, EPR, optical and structural studies

Strontium borate glasses containing Indium oxide with chemical composition 69B2O3–(30-x) SrO- xIn2O3-1CuO varying ‘x’ from 0.5 to 2.5 mol% were synthesized by quenching method. The non-crystalline characteristics of these glasses were established by X-Ray diffraction patterns. Physical parameters like density (ρ), molar volume (Vm), dielectric constant (ε) and other properties were described with varying mole percent of indium oxide. Spectroscopic findings, viz. optical absorption, EPR were conducted to understand the influence of In2O3 and CuO on strontium-borate glass network. Optical energy band gap (Eopt) and Urbach energies were calculated. Spin-Hamiltonian values from EPR of Cu2+ spin probes obeyed g‖‖> g⊥>ge and A‖‖> A⊥ revealing dx2-y2 (2B1g state) as ground state of Cu2+ ions and site symmetry in the neighbourhood of Cu2+ is tetragonally distorted octahedral. FTIR studies established the existence of typical BO3, BO4 units in addition to In3+O6 groups. The various Raman peaks shown by the glass samples were appropriate assigned and corresponding structural variations were discussed.

FTIR and Raman analysis of PbBr2-CdO-Bi2O3-B2O3 glasses

With the use of physical and structural analysis, the current study will examine the impact of PbBr2 on borate glasses containing heavy metal oxides. In contrast to their opposite trends, the density and molar volume showed an increasing trend in this system of glasses. These glasses developed high density with increased PbBr2 content, similar to the previously described glasses with heavy metal oxides and PbBr2. The locations of the Raman bands were determined from the deconvoluted Raman spectra and are attributed to the corresponding vibrations. FTIR spectra showed that the glass structure contained BO3, BO4, BiO3 units, etc. The characteristic bonds in FTIR spectra revealed that Bi2O3 is acting as glass modifier in the spectra. The increase in PbBr2, made the BO4 units to increase and hence increase in density.

KMB4O6F3 (M = Co, Fe): two-dimensional magnetic fluorooxoborates with triangular lattices directed by triangular BO3 units.

Frustrated magnetic systems are of great interest owing to their spin liquid state for application in quantum computing. However, experimentally, spin liquid has not been realized. Thus, experimental explorations of frustrated magnetic systems including triangular lattices are still urgent, particularly for directed synthesis compared to random exploration. Herein, for the first time, directed by the use of a triangular unit of the BO3 anion group, two novel layered magnetic fluorooxoborates KMB4O6F3 (M = Co 1, Fe 2) with triangular lattices have been hydrothermally synthesized and characterized. Compounds 1 and 2 are isostructural and crystallize in the P21/c space group with layered magnetic triangular lattices, which are further separated by K+ ions. Magnetic susceptibility curves of both 1 and 2 show no λ-anomaly peak down to a low temperature of 2 K in the absence of a magnetic long-range ordering transition, which are further confirmed by the heat capacity results. The magnetic-field dependence of magnetization at 2 K shows saturation of 2.20μB for 1 and 4.24μB for 2, respectively, at 7 T, after roughly subtracting the Van Vleck paramagnetic contribution. Further in-depth investigation of the underlying physics at a lower temperature below 2 K would be subsequently performed. Moreover, thermal stability and FT-IR and UV-vis-NIR spectroscopy with optical bandgap properties are also reported. Most importantly, our work provides a promising method to experimentally realize specific magnetic lattices (e.g. triangular lattices) directed by the use of triangular groups (e.g. BO3) as the functional unit.

Physical and spectroscopic properties of PbO –ZnF2 – B2O3 glasses doped with CuO

The glass samples with the chemical composition of PbO − ZnF2 − B2O3: CuO has been prepared by melt quenching technique. All the prepared glass samples exhibits amorphous nature, were confirmed by the X-ray diffraction studies. The density of the glass samples were measured by using Archimedes’ principle. With help of measured densities various physical properties such as average molecular weight (M¯), molar volume, Interatomic distance(ri), dopant ion concentrations (Ni) were calculated by using standard formulas. Optical Absorption spectra studies reveals that the glass samples contains Cu ions exhibits a broad absorption band at about 780 nm due to 2B1g→2B2g transition.The spectra of Infrared transmission show prominent bands at wave numbers around 1200 to 1400 cm−1, which are caused by the trigonal BO3 units, at 1000 and 1200 cm-1which are caused by vibrations of BO4 structural units, and at about 700 cm−1 which are caused by B-O-B linkages.

Structure and fragility of normal and invert lanthanum borate glasses: Results from 11B and 17O NMR spectroscopy and calorimetry

The structure of select normal and invert (La2O3)x(B2O3)100-x glasses with 22 ≤ x ≤ 60, synthesized using conventional and containerless levitation melt-quenching, is studied using 11B and 17O NMR spectroscopy. The results indicate that the structure of normal glasses with 22 ≤ x ≤ 30 is characterized by a borate network of B-O-B bridging oxygen (BO) linkages between BO3 and BO4 units and non-bridging oxygen (NBO) with La acting as a charge balancing modifier cation. In contrast, the invert glasses with 55 ≤ x ≤ 60 consist of a network of La-O polyhedra connected via La-O-La linkages i.e. “free-oxide” ions and via La-NBO-B linkages with interspersed [BO3]3− units. This structural evolution in lanthanum borate glasses is consistent with the composition dependence of their glass transition temperature. The temperature dependent boron and oxygen speciation in these glasses are linked to their calorimetrically determined fragility index.

Synthesis, structure and properties of PbO–PbF2–B2O3–SiO2 glasses

The structure, thermal and some physical properties of lead fluoroborate glasses containing 30 mol% SiO2 have been investigated by differential thermal analysis, X-ray diffraction and Fourier-transform infrared spectroscopy. The glasses were prepared by the conventional melt-quenching method. Fourier-transform infrared spectroscopy results showed that the network of these glasses consists mainly of BO3, BO4, SiO4, and PbO4 structural units. The thermal stability of the glass samples determined by differential thermal analysis was found to be about 80°C. Dilatometric measurements showed that the glass transition temperature and dilatometric softening temperature decrease with increasing lead content, whereas the coefficient of thermal expansion increases. The density and molar volume increased with the increase in lead content. The conductivity of the investigated glasses mainly depends on the mobility of F– and Pb2+ ions. The variation in volume resistance upon changing the composition has been correlated with the structural changes in the glass network. The results obtained in this study indicate that the investigated glasses can be potential candidates for advanced technologies as solder and sealing materials.

Structural, thermal, and DC conductivity properties of WO3–P2O5 glasses doped with B2O3

AbstractIn this study, glasses in composition 70WO3–(30 − х)P2O5–хB2O3 (0 ≤ х ≤ 20 mol%) were prepared by melt quenching method. The glass formation, structure, and thermal and electrical properties are discussed. Homogeneous glasses were obtained at x = 0–10 mol% B2O3, whereas glasses with x = 15 and 20 contain microinclusions of WO3. The glass transition temperature decreases from 709 to 531.6°C with increasing B2O3 content, as well as the crystallization temperature and the thermal stability. The structure of the glasses was studied by Raman spectroscopy and infrared spectroscopy. The Raman spectra are characterized by a band near 995 cm−1, a broad band at 788–800 cm−1, and a band near 675 cm−1 ascribed to vibrations of W–O–P, W–O–W, and P–O–B bonds, respectively. The Fourier‐transform infrared spectra show vibrational bands due to characteristic phosphate and borate groups. Tetrahedral BO4 units prevail in the structural network. The electrical conductivity of the glasses decreased with x content due to the growth of WO3‐deficient regions.

Effect of MoO3 on Na2O–B2O3–CdO–ZnO glasses: Applications in optoelectronics, communication devices, and radiation shielding

The current study focuses on the physical and structural aspects of B2O3–CdO–ZnO–Na2O glasses that have been reinforced by MoO3 ions. The samples were experimentally prepared using a melt quenching procedure, and then the absence of strong peaks in the XRD spectra confirms their amorphous nature. A variety of optical, Raman, and radiationshielding qualities were evaluated and described. The structural changes in the material were investigated using FTIR and Raman spectra. The density of the samples rose when MoO3 was added, implying that BO3 was transformed into BO4 units. The transition of Mo6+ to Mo5+ ions is responsible for the reduction in band gap in these glasses. Because of the vacancy generated by the oxygen units, the Urbach energy increased, implying the generation of additional defects. The presence of diverse structures present in the structure of the glass was revealed by FTIR and Raman spectra, such as MoO6, BO3, BO4, metaborates, pyroborates, and so on. The transition of BO3 to BO4 units, which is crucial in density analyses, was also corroborated by Raman spectra. Using FLUKA simulation and XCOM estimations, the mass attenuation coefficient of the glasses improved with the amount of MoO3. At 15 keV, the half-value layer of 0.0103 cm, 0.01019 cm, 0.01016 cm, 0.0101 cm, and 0.01005 cm was obtained for glasses with an MoO3 concentration of 0, 0.5, 1, 1.5, and 2.0 mol% respectively. The optimum MoO3 concentration for fast and thermal neutron cross-sections was 0.5 and 2.0 mol% respectively. The glasses are viable materials for environmentally friendly and transparent radiation barriers in nuclear facilities.

Physical, structural, thermal, and mechanical features combined with neutron and gamma radiation attenuation qualities of Sm2O3 doped transparent borate-rich glasses

Current work presents the synthesis of B2O3–Gd2O3–Li2O–Na2O–LiF‒Sm2O3 glass system via melt-quench approach and scrutiny of its mechanical, thermal, structural, physical, and nuclear radiation attenuation aspects. Raman scattering and Fourier transform infrared spectra revealed B–O stretching modes of BO4 groups linked to BO3 units with nonbridging oxygen atoms and BO3 and BO4 units' existence in the glass structure. By differential scanning calorimetry, glass transition and crystallization temperatures are identified. Relevant analysis showed all glasses' good thermal stability where glass transition temperature varied at 372–407 °C range. ΣR (fast neutron removal cross-section) and for energy 0.025 eV neutrons σT (total cross-section) are computed. In all glasses, 49.25 B2O3–10Gd2O3–10Li2O–10Na2O–20LiF-0.75Sm2O3 (mol%) sample holds higher ΣR (= 0.10207 cm−1). 48B2O3–10Gd2O3–10Li2O–10Na2O–20LiF–2Sm2O3 (mol%) glass possesses greater σT (= 736.675 cm−1) for thermal neutrons, hinting at added Sm2O3's favorable influence as Sm owns a better ability for neutron absorption than B. By Phy-X/PSD, μ/ρ (mass attenuation coefficient) is obtained at photon energy extent 15 keV‒15 MeV. Sm2O3 inclusion from 0 to 2 mol% minorly enhanced the μ/ρ values. Buildup factors estimated via geometric progression fitting method at 1–40 mean free path and energy 0.015–15 MeV span are maximal at medium energy region owing to Compton scattering process. 48B2O3–10Gd2O3–10Li2O–10Na2O–20LiF–2Sm2O3 (mol%) sample shows superior γ-ray blocking capacity in all glasses, suggesting Sm2O3's positive effect. Elastic moduli and Poisson's ratio are computed theoretically by bond compression and Makishima–Mackenzie models. It is identified that all glasses could tolerate longitudinal stress over shear stress.

Effect of CeO2/Er2O3 co-doping on spectroscopic properties of zinc fluoroborate glasses

The glass system 75B2O3—4.5ZnF2—0.5 Er2O3–(20-x) ZnO- x CeO2, x = (0 ≤ x ≤ 1 mol. %) in this article was produced using the melt-quenching technique. Utilizing FT-IR techniques, the structural specifics of manufactured glasses are studied. The and fractions will be used to explore the transformation in the glass system that has been obtained. The BO3 and BO4 units coexisted in the glass composition, based on FT-IR spectra. Cerium ions appear to change trigonal BO3 units into tetrahedral BO4 units, according to preliminary FT-IR studies. The Judd-Ofelt theory is used to calculate the optical properties of the current glass that is co-doped with Er/Ce. Energy levels and line strengths of the Er3+ ion are evaluated. The current work additionally provides optical gains, emission/absorption cross-sections, and optical intensity data. The compound containing 0.6 mol% provided the greatest values for optical parameters like intensity parameters and optical gain compared to all other concentrations employed in this study.

The impact of electron beam irradiation on some novel borate glasses doped V2O5; Optical, physical and spectral investigation

New borate glass systems with composition of 56B2O3 + 25Li2O + 10Na2O + 5CaO + 2SrO + 2Al2O3 + 0.5 TeO2 + x V2O5, where × = 0.2 or 0.3 (wt. %), were fabricated via the traditional melting-annealing method at low temperature (650–750 °C). Some of the glasses optical, physical, chemical and spectral measurements were investigated within the impact of electron beam (EB) irradiation up to 8 kGy. UV–visible spectra revealed peaks at ∼ 290 and ∼ 300 nm for 0.2 and 0.3 V2O5 glasses, respectively. In addition to broad visible band at ∼ 580 nm owing to the participation of vanadium ions as V5+ with possible conversion to V3+/V4+ under the effect of EB irradiation. FTIR spectra revealed the main trigonal BO3 and tetrahedral BO4 units with an increase in N4 values by the progressive EB irradiation. ESR spectra revealed a gradual increase in intensity with irradiation doses. While, testing chemical durability in distilled H2O at 100 °C reveals a good manner before and after irradiation process. Some physical parameters e.g. optical energy gap (Eoptdirect and Eoptindirect), Urbach energy (EUrbach), refractive index (n) and spectral distribution (k) showed also a gradual decrease with continual irradiation owing to the gradual generating of non-bridging oxygens NBOs and progressive transformation of BO3 to BO4 units. The overall data displayed some dosimetric properties of the two studied glasses with a useful dose range 3–8 kGy of EB radiation. The study recommends usage of glasses as glass dosimeters in medical sterilization, industry and food irradiation processing.

Impact of MoO3 on physical and spectroscopic (optical, FTIR, Raman and EPR) studies of B2O3-CdO-Al2O3-ZnF2 glasses for optical and shielding applications

In this study we have prepared the specific composition 60B2O3–20CdO-5Al2O3-(15-x)ZnF2-xMoO3 (where x = 0, 0.5, 1, 1.5, 2) samples by using conventional Melt quenching method. The structural properties of the glass samples were characterized by using FTIR, Raman spectroscopy and X-Ray diffraction. The analysis of FTIR spectra divulges the existence of contrasting borate and aluminates units and also specifies the conversion of Mo6+ to Mo5+. As increasing of MoO3 concentration the density of glass materials is enhancing slightly. With increasing of MoO3, the decrease in the optical band gaps is observed in the studied compositions. This is happen due to the transformation of Mo6+ ions to Mo5+ ions will enhance of Non-Bridging oxygen concentration with increasing of MoO3. The analysis of Raman spectra suggested that BO4 units are transformed to BO3 units with increasing of MoO3 concentration. With increasing of BO3 units, the non-bridging oxygen’s levels will improve which in turn enhances the density of the compositions.

Structure-Property Correlation in Sodium Borophosphate Glasses Modified with Niobium Oxide

Bulk glasses of the series (100−x)[0.4Na2O-0.2Nb2O5-0.4P2O5]-xB2O3 with x = 0–48 mol% B2O3 were prepared by slow cooling in air. Their glass transition temperature increases within the range of 0–16 mol% B2O3, but further additions of B2O3 result in its decrease. Their structure was investigated by Raman, 11B, and 31P MAS NMR spectroscopy. The relative number of BO4 units decreases with increasing B2O3 content, while the number of BO3 units increases up to 59 % at x = 48. The upfield shift of a broad resonance peak in the 31P MAS NMR spectra is ascribed to an increasing connectedness of the structural network with increasing B2O3 content. Strong Raman band at 916–929 cm−1 shows on the presence of NbO6 octahedra in the structural network of these glasses. With the B2O3 addition, a decrease in DC conductivity is observed, which is attributed to the decrease in the concentration of Na+ ions.

Influence of La3+ ions on the structural, optical and dielectric properties and ligand field parameters of Fe3+ hybrid borate glasses

The effect of TM/RE mixture (i.e., Fe3+/La3+) on the optical, structural and dielectric features of alkali borate glass was investigated. XRD spectra showed the successful formation of the glass matrix. The La2O3 doping as a network modifier imposed some structural modifications, such as a ∼20% growth in density, ∼15% reduction in molar volume, and an increase in the proportion of BO4 units with a decrease in NBO's ratio. The optical spectra associated with Fe3+ ions occupying the tetrahedral and octahedral sites were subjected to tunability within the visible range by La2O3 additions. Many optical and dielectric features are greatly enhanced; Such as bandgap energy, Urbach energy, linear/nonlinear refractive index, dielectric constant and dielectric loss. The metallization criterion decreased from 0.368 to 0.364 eV−1, reflecting the semiconductor nature of the samples. The nephelauxetic effect confirmed the covalent bonding nature of Fe3+ ions, consistent with the results of ESR spectra.

Effect of B2O3 and Li2O on vibrational, thermal and optical properties of 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (0 ≤ x ≤ 25 mol%) glasses

Bi2O3 based glasses have been proven as promising optical materials with regard to their 6 s2 lone pair electrons. By melt quenching, the highly thermal stable glasses 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (where 0 ≤ x ≤ 25 mol%) were prepared. The short range order of the glasses was verified with XRD and DSC measurements. DSC analysis showed that thermal parameters varied non-linearly with increase of Li2O. Density (ρ), molar volume (Vm), oxygen packing density (OPD) and oxygen molar volume (Vo) were calculated and their compositional dependency was discussed in detail. Energy dispersive X-Ray (EDX) spectrometry analysis validated the stoichiometry of sample composition. FTIR analysis illustrated that the glass network comprise of BiO3, BiO6, BO3 and BO4 structural units together with non-bridging oxygens. The computed optical properties like optical band gap (Eopt), refractive index (n), Urbach energy (∆E), molar refraction (RM), metallization criterion (M) and oxide ion polarizability (αO2-) were observed to be non-linearly varied with the addition of Li2O. The interplay between the structural roles of Li2O and Bi2O3 was instrumental for the observed variations in all the properties. BiPBL4 glass showed the highest thermal stability (175 °C) and the high kgl value among the glass series. The incorporation of Li2O in presence of low mol% of B2O3 with Bi2O3-PbO endowed these glasses to have the low phonon energy. The analysis carried out in this work showed that these glasses might useful for optoelectronic devices and optical fiber drawing applications.