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Borogermanate glasses containing terbium ions are interesting materials due to their luminescent and magnetic properties. Terbium can present two different oxidation states and the thermal poling technique can be a pertinent way to modulate spatially the oxidation state of these ions. In this work, we demonstrate using a thermo-electrical imprinting process the transfer of micro scaled motifs on the surface of a borogermanate glass containing Tb ^3+ resulting in a micrometric structuring of the oxidation state of Tb ^3+ /Tb ^4+ ions. A large change in absorption and luminescence optical properties is observed, arising from the distinct properties of trivalent and tetravalent terbium ions. Correlative micro luminescence, Raman and second harmonic generation measurements were carried out on the patterned poled glass surface. This has demonstrated an accurate concomitant modification of the glass structure accompanying large luminescence changes and the appearance of a second order optical response which could be attributed to a localized space charge implantation. These original results demonstrate how a simple electrical process allows managing multi optical properties but also paves the way to induce static electrical functionalities in a magnetic optical glassy system.

Glasses and glass-ceramics based on the Tb3+-doped SbPO4-GeO2-Al2O3 composition have been studied. Samples containing up to 0.4 mol % of Tb4O7 form glasses when obtained by melt-quenching while concentrations above that tends to form glass-containing single crystals. This work reports the thermal, structural, morphological, and optical studies of (96-x)(40SbPO4-60GeO2)-4Al2O3-xTb4O7 samples (where 0.2 ≤ x ≤ 0.7, in mol %) using Differential Scanning Calorimetry, X-ray Powder Diffraction, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, UV–Vis absorption, Raman, and Photoluminescence spectroscopies. The diffraction pattern for the glass-ceramic containing 0.7 mol% of Tb4O7 shows diffraction peaks, which were assigned to the crystalline phase derived from terbium orthophosphate (TbPO4). In the same direction, the Raman spectra of the glass-ceramics containing 0.5, 0.6, and 0.7 mol% of Tb4O7 exhibited narrow bands in the region between 900 and 1300 cm-1, which are characteristic of the main vibrational modes of the PO4 tetrahedral units of TbPO4. The TbPO4 crystals exhibited an average size distribution ranging from 10 to 200 μm. The TbPO4 crystals exhibited an unusual morphology and design, resembling the shape of the letter ''H'' and is completely different from the crystals reported in the literature. Strong green emission from TbPO4 crystals was verified at 547 nm for all samples. The emission spectra showed not only bands assigned to 5D4→7FJ electronic transitions in the green-red range, but also those coming from 5D3→7FJ in blue region.

Tellurite glasses are considered a potential alternative for applications not achieved by SiO2-based glasses, presenting interesting optical properties, such as high linear and nonlinear refractive indexes, extended optical window, being also suitable for metallic nanoparticle growth, like Te0. When doped with sulfide species, it can benefit the reduction of Te4+ to Te0, which can be advantageous to synthesize in-situ chalcogenide nanoparticles and quantum dots. This work presents investigations on the reduction of Te4+ to Te0 in tellurite glasses doped with PbS and PbO/ZnS, and aims to control this redox process through the processing with pulsed fs-laser. Tellurite glass samples were synthesized by melt-quenching technique and the thermal and structural properties were explored by different techniques, such as DSC, Raman scattering spectroscopy and mapping experiment, TEM and SAED. Reduction of tellurium to Te0 nanocrystals into tellurite glass after laser irradiation was studied in detail and confirmed by the presence of bands at ~120 and 140 cm−1 in Raman spectroscopy and mapping, assigned to the Te–Te vibrational modes, which suggest that S2− induces in-situ Te4+ reduction. Moreover, quasi spherical tellurium nanoparticles were observed through TEM and confirmed their chemical nature and crystallization by SAED. The study of tellurium reduction in the vitreous matrix becomes particularly important and promising for some applications, since its reduction generates changes in the refractive index by precipitation of Te0 nanoparticles, allowing the fabrication of waveguides and as photosensitive material for tridimensional data storage.

Abstract New glass compositions containing high concentrations of Tb3+ ions were developed aiming at the production of magneto-optical (MO) fibers. This work reports on the structural and MO properties of a new glass composition based on (100 − x)(41GeO2–25B2O3–4Al2O3–10Na2O–20BaO) − xTb4O7. Morphological analysis (HR-TEM) of the sample with the highest concentration of Tb3+ ions confirmed the homogeneous distribution of Tb3+ ions and the absence of nanoclusters. All the samples presented excellent thermal stability against crystallization (ΔT > 100 °C). An optical fiber was manufactured by a fiber drawing process. The UV–Vis spectra of the glasses showed Tb3+ electronic transitions and optical windows varying from 0.4 to 1.6 μm. The magneto-optical properties and the paramagnetic behaviors of the glasses were investigated using Faraday rotation experiments. The Verdet constant (VB) values were calculated at 500, 650, 880, 1050, 1330, and 1550 nm. The maximum VB values obtained at 650 and 1550 nm for the glass with x = 18 mol% were -128 and − 17.6 rad T−1 m−1, respectively. The VB values at 500 and 1550 nm for the optical fiber containing 8 mol% of Tb4O7 were − 110.2 and − 9.5 rad T−1 m−1, respectively, while the optical loss at around 880 nm was 6.4 dB m−1.

New magnetic glass compositions, based on system (100-x) (60GeO2 -25B2O3 –4Al2O3 -10Na2O–1PbO) – xTb4O7 were prepared by the melt-quenching technique. The materials were systematically characterized with respect to their structural (XRD, EXAFS, XANES and Raman), thermal (DSC), morphological, optical, magnetic and magneto-optical (MO) properties. Morphological and magnetic measurements show the homogeneous distribution of the Tb3+ ions as the magnetic susceptibility increases proportionally to the rare earth content. The optical window covers the range from 0.5 up to 1.6 μm, limited by absorption due to 4f8 -> 4f7 5 d 1and 4f8 -> 4f8 transitions of Tb3+. XANES and EXAFS measurements at the Ge–K edge show that the germanium atoms are always tetrahedrally coordinated, while results at the Tb-LIII edge shows terbium atoms to be eight-coordinated and exclusively present in the oxidation state 3+ independently of the glass composition. MO measurements show that the Verdet constant (VB) increases linearly with the Tb3+ concentration reaching the value of −83.9 rad T−1m−1 at 650 nm for glass containing 8 mol% of Tb4O7. Good thermal stability (ΔT = 200 °C) allowed obtaining an optical fiber of a glass containing 4 mol% of Tb4O7 featuring VB values of −37.9, −23.6 and −5.89 rad T−1 m−1, at 500, 650 and 1550 nm, respectively.

Glass is a familiar material that requires abundant mineral sources, with devastating consequences for the environment. Rice husk ash (RHA) presents a very high silica content (>95%) and it can be a very promising alternative source for silica in silica-based glass. However, impurities like manganese and iron, which depend on the rice harvest, might limit RHA use, particularly in the production of optical transparent glasses. In this work, we discussed how Mn and Fe can affect the coloring of the produced glass, and how the effect of these impurities can be removed. First, the RHA was treated with acid solutions, leading to the production of a soda-lime glass with similar transparency to commercial glass (>70%). Secondly, another simpler approach was studied: a small amount of antimony oxide was added in the composition of the glass, obtaining a transparent glass (>80%, same thickness) with RHA.

Bacterial nanocellulose (BNC) is a natural biopolymer obtained by gram-negative bacteria by means of a green and inexhaustible biotechnological process using glucose as producing source. BCN hydrogels is formed by cellulose nanofibrils that maintain an open network structure, an ideal matrix to produce new class of organic-inorganic nanocomposites (OIN) for multifunctional applications. The polyoxometalates (POMs) are complex molecules with several metallic ions sharing oxide ions, forming a highly symmetrical metal oxide cluster. Phosphotungstic acid (PWA), H3PW12O40 photoreduction process activated under ultraviolet irradiation, promoting color change. In this work, photochromic organic-inorganic nanocomposites were prepared by soaking phosphotungstic acid (H3PW12O40) in wet BNC membranes mats at room temperature. Semi-transparent and free-standing BNC/PWA nanocomposite with paper-like aspect were obtained. BNC network was able to control, stabilize and disperse PWA particles in a narrow nanometric distribution, and FTIR spectra indicated that the primary Keggin structure was also preserved in the nanocomposites, independently on the PWA content. The nanoparticles present a narrow distribution of around 16 nm, independently on the PWA concentration. BNC/PWA nanocomposites showed reversible photochromic behavior characteristic of the equilibrium between different tungsten oxidation states. PWA reduction (W6+→ W5+) and organic matrix oxidation is proposed to occur through a radical process involving the interaction of one electron from the oxygen atom of the PWA and one hydrogen from BNC matrix. The photochromic effect vanishes almost completely after 5 h. This mechanism is real in the presence of oxygen, however, if the membranes are left in nitrogen or under vacuum the blue color remains longer than 45 days. Photo-electrochemical behavior was studied by spectroelectrochemistry measurements. It is worth noting that all processes were still reversible in the timescale of the experiment and color changes were observed in several cycles.

Historical research of public spaces provides a better understanding of the social formation and preserve cultural and landscaping heritage. José Bonifácio Square, located in Picacicaba, São Paulo State, Brazil, is an important public space. We carried out a historical survey in the archives of municipal public institutions and a landscape record was done by identifying tree species implanted in the square. We verified a strong church influence in the development of the square landscape project. The first landscaping work occurred in 1885, and it became known as City Public Garden. It presented naturalistic features, using exotic and native species, mainly trees, for landscaping composition. Several modifications and reforms were made from 1885 to 2005. José Bonifácio Square was considered highly diverse (H’ = 3.18) with 151 individuals, distributed in 36 species belonging to 14 botanical families. The native species from Atlantic Forest represented 82.6% of Bignoniaceae, Arecaceae, and Fabaceae species. The high diversity of native species found in José Bonifácio Square allowed us to infer a lower ecological fragility and a higher environmental balance than other Brazilian squares. The analysis of historical information from the years 1885 to 2019 and the analysis of the square’s floristic composition in contemporary times demonstrated José Bonifácio Square’s relevance in forming and conserving Piracicaba’s urban identity.

The development of glasses containing nanoparticles dispersed homogeneously with controlled size and optimum parameters for functionality is a challenge. Glasses in the ternary system 60SbPO4-30ZnO-10PbO containing CdFe2O4-SiO2 nanoparticles were studied. The CdFe2O4 nanoparticles were synthesized by the coprecipitation method and the average size was 3.9 nm and then, they were protected by a silica layer. The nanoparticles were mixed with the glass precursors and transformed into glasses by melt-quenching method. Thermal and structural properties were evaluated by differential scanning calorimetry, Raman spectroscopy, scanning electronic microscopy and transmission electron microscopy. While the optical properties were studied by M-Lines spectroscopy and UV-VIS spectroscopy. The glass samples obtained were completely transparent, with amber color and showed no sign of crystallization according to the techniques used. Scanning and transmission electron microscopy confirm that the methodology used for the incorporation of nanoparticles was efficient. The nanoparticle protection methodology prior to incorporation into glasses may contribute towards the development of glasses containing nanoparticles useful for magneto-optics devices.

Glasses in the ternary system (Sb2O3)(0.6-x)(SbPO4)(0.4)(WO3)(x), with composition 0.1 £ x £ 0.5 were studied. The structural changes due to the replacement of Sb2O3 by WO3 have been investigated. It was found that the incorporation of WO3 enhances the thermal stability of the glasses against devitrification when compared to the binary Sb2O3(0.6) - SbPO4(0.4) composition. The connectivity of the network increases with WO3 content which is consistent with the high values of the glass transition temperature. Raman studies suggest that WO3 incorporation breaks the primary network, constituted by antimony oxide, while a second network containing WO6 octahedral units is built up. Thermal and structural properties were evaluated by differential scanning calorimetry, infrared and Raman spectroscopies, 31P Magic Angle Spinning NMR and X-ray absorption near edge structure (XANES) at L1 and L3 edges of Sb and L1 edge of W atoms.

Pressure on tropical forests by agriculture and livestock expansion, frequently leads to highly fragmented and isolated populations. Limited gene fow drives increased drift and genetic differentiation among populations, ultimately reducing the overall genetic diversity of forest tree species. Balforoudendron riedelianum (Engl.) Engl., commonly known as pau marfm (ivory tree), a valuable Brazilian hardwood tree used in carpentry and building, is currently endangered due to logging and forest fragmentation. Information on genetic diversity and structure of remnants populations is necessary to support its conservation and sustainable management. Microsatellite markers are an effective tool for understanding and quantifying the effects of fragmentation on genetic diversity. Seven microsatellite markers were developed and validated using a sample of 98 individuals. The number of alleles per locus ranged from 3 to 25, the observed and expected heterozygosities from 0.051 to 0.909 and 0.050 to 0.930, respectively, the fxation index corrected for null alleles from 0.036 to 1.0 and all markers were found in linkage equilibrium. This microsatellite marker set is suitable to estimate population genetic parameters in support of sustainable management and conservation, and to assess relatedness and parentage in breeding populations.

In this second part it will be discussed some photonic applications of glassy and glass ceramic thin films which can be used as planar waveguides. Some photonic applications require certain specifications of glass, which can be quantified by studying the nonlinear optical properties of the materials. Therefore, a brief introduction of these phenomena is discussed, as well as the use of femtosecond lasers to manipulate the composition or for the preparation of waveguides into glasses. Finally, the article will address a brief introduction on microstructured optical fibers and commercial application prospects for these devices.

2015 is the Year of Light, according to UNESCO. Chemistry has a close relationship with light and one of the materials that allows such synergy is glass. Depending on the chemical composition of the glass, it is possible to achieve technological applications for the whole range of wavelengths extending from the region of the microwave to gamma rays. This diversity of applications opens a large range of research where chemistry, as a central science, overlaps the fields of physics, engineering, medicine, etc., generating a huge amount of knowledge and technological products used for humanity. This review article aimed at discussing some families of glasses, illustrating some applications. Due to the extension of the theme, and all points raised, we thought it would be good to divide the article into two parts. In the first part we focus on the properties of heavy metal oxide glasses, fluoride glasses and chalcogenide glasses. In the second part we emphasize the properties of glassy thin films prepared by sol-gel methodology and some applications, of both glasses as the films in photonics, and more attention was given to the nonlinear properties and uses of photonic fibers.

In this work we report a systematic study on the influence of the chemical nature of silver precursors on the formation of glass-ceramics from oxide glasses. Thermal, structural and optical properties were analyzed as a function of the glass composition. Controlled crystallization was achieved by thermal treatment of the samples above glass transition. The influence of time of treatment on both nanoparticle growth and optical properties of the samples was studied by transmission electron microscopy and UV-Vis spectroscopy, respectively. Results showed that only glasses containing AgCl and AgNO3 led to glass-ceramics growth after thermal treatment.

Silver containing heavy metal oxide glasses and glass ceramics of the system WO3-SbPO4-PbO-AgCl with different AgCl contents have been prepared and their thermal, structural and optical properties characterized. Glass ceramics containing metallic silver nanoparticles have been prepared by annealing glass samples at temperatures above the glass transition and analyzed by transmission electron microscopy and energy dispersive X-ray microanalysis. The presence of the metallic clusters has been also confirmed by the observation of a surface plasmon resonance band in the visible range. Cyclic voltammetric measurements indicated the presence of metallic silver into the glasses, even before to perform the thermal treatment.