IYOG: Certev

Participants of the CeRTEV’s Advanced International Glass and Glass Ceramic School in 2015. �

Glass Science in Brazil

In the International Year of Glass, Andrea Simone Stucchi de Camargo* discusses some of the developments that have taken place in glass science and explains how we are on the threshold of an exciting decade of research.

Glass research in Brazil is relatively young, but quite vigorous. According to the database of the National Council for Scientific and Technological Development (CNPq) [1] , academic research is distributed mainly in public universities and research institutes located in the southeast and south part of the country with a few, but important, exceptions in the northeast.

The state of São Paulo leads the efforts and hosts 33% of the most prolific research groups, followed by the states of Minas Gerais, Paraná, Pernambuco, Alagoas, and others.

Inland São Paulo state, a strong cluster within a radius of less than 100 km, is formed by different units at the Federal University of São Carlos (UFSCar), at the University of São Paulo (USP) in São Carlos and in Ribeirão Preto, and at the São Paulo State University (UNESP) in Araraquara.

In the state capital, there are groups at the Technology College FATEC, and at the research institutes IPEN and IPT.

Furthermore, the state also hosts the largest and most important glass industries in the country with production ranging from kitchenware and construction materials to technological glasses and glass ceramics (Fig 1).

The beginning of Brazilian glass research dates back to 1973 when Aldo Felix Craievich relocated from the University of Cordoba in Argentina and became a faculty member at the Institute of Physics and Chemistry of USP in São Carlos. In 1975 he published the first two papers on the phase transformation of lead aluminoborate glasses.

In 1981, after having moved to the Brazilian Center of Physical Research (CBPF), he published the first theoretical paper based on dynamic scaling in the same glass system.

Following the footsteps of Craievich, his disciple, Edgar Dutra Zanotto was the first scientist to introduce research on crystal nucleation in glasses in Brazil, in 1977. To date he remains the most prolific researcher in the area. He created the Laboratory of Vitreous Materials (LaMaV) at UFSCar, even before he completed his PhD with Peter F. James in Sheffield, UK, in 1982.

In 2001, alongside his colleague Oscar Peitl, they published a highly cited (> 400) manuscript with Larry Hench - the inventor of bioglasses, and since then LaMaV became an international reference group in that area.

The 1970‘s were favourable years for scientific research in Brazil, when many important academic institutions such as UFSCar were established. It was in that university that the first undergraduate curriculum on Materials Engineering in Latin America, was introduced. Over the 1980’s and 90’s highly motivated scientists such as Luiz Carlos Barbosa, Sidney José Lima Ribeiro, Cid Bartolomeu de Araújo, Mauro Luciano Baesso, Younès

CeRTEV team of principal and associate investigators and researchers.�

Messaddeq and Noélio Oliveira Dantas introduced different approaches to glass research in their institutions, which remain active to these days.

Besides being the most prolific and internationally active scientists in the field, they have actively contributed to the nucleation of many other research groups.

Besides the focus on structure and crystallisation, the Brazilian glass science production strongly emphasises optical glasses, especially those doped with active rare earth ions. Some important initiatives markedly contributed to boosting glass research after 2010.

In that year, a research agreement was signed between the Center of Optics, Photonics and Lasers at the university of Laval, in Canada, and the Chemistry Institute of UNESP, by initiative of Younès Messaddeq.

Through that partnership, scientific and technological development, as well as student and researchers mobility have been in place between the two institutions.

In 2013, a major investment from the São Paulo Research Foundation (FAPESP) allowed the establishment of the Center for Research Technology and Education on Vitreous Materials (CeRTEV). The centre is directed by Zanotto and Hellmut Eckert, who became a faculty member of the São Carlos Institute of Physics IFSC/ USP in 2011 and since then has given major contributions to the Brazilian glass research via solid state NMR and EPR studies. CeRTEV conducts research and develops technology in the areas of reinforcement materials, bioglasses and bioceramics, fast ion conductors, optical and catalytic materials.

It is composed of 14 faculty members (9PIs) from UFSCar, USP and UNESP and to this date it has produced more than 400 publications that received more than 6,000 citations.

In addition to FAPESP, CeRTEV is also externally funded by joint projects with national and international industry.

The experimental and theoretical competences of the center are quite encompassing, from the most fundamental aspects of structure, nucleation and crystallisation of glasses to biological, electrical, optical and magnetic applications.

� Fig 1. Glass research and production in academic institutions and industries in the state of São Paulo, Brazil.

During the nine years since its funding, it has been able to establish an excellent infrastructure, complemented by access to other facilities in the involved universities and the National Synchrotron Lab in Campinas. A careful analysis, focused on inorganic glasses, indicates that in the past five years CeRTEV has contributed with about 25% of the quantitative research output from Brazil, and the total contribution of the country to the field (since 1975) is estimated around 2.9%.

Besides research and innovation, an equally important part of CeRTEV´s mission is to provide education and diffusion of knowledge. More than 60 students have obtained their Masters or PhD degrees in the framework of the centre and in 2015 the CeRTEV’s Advanced International Glass and Glass Ceramic School attracted about 100 students, half of which came from about 30 countries. Furthermore, together with the Brazilian Association of Automated Glass Industries (ABIVIDRO) and the public technical school Paula Souza Center, CeRTEV has developed and implemented the first full curriculum for a three-semester professional degree in glass technology in Brazil. The purpose is to create human resource to strengthen the innovation potential of the Brazilian glass industry.

Besides an extensive list of academic and industrial collaboration partners, CeRTEV is regularly evaluated by its International Advisory Board, made up by distinguished scientists and partners in industry from North America, Europe and Asia. Upon those evaluations the centre reasses and sharpens its scientific, innovational and educational goals. Scientific highlights include the research carried out at LaMaV by Zanotto and Peitl on the development of bioactive gels, glasses and glass ceramics for medical and dental restauration and tissue regeneration which have resulted in various patents and a spin-off company.

The research on fast ion conducting glass ceramics is also quite promising. Recently, H. Eckert and Ana Candida Martins Rodrigues from CeRTEV have authored a study published at the J. Chem. Phys. in collaboration with Philip Salmon from the University of Bath, UK, which develops a structural model of the glass to crystal transition in the NGP glass ceramic based on combined neutron diffraction and solid-state NMR [2] .

It is a relevant study because NGP is a prototype for glass ceramics with the NASICON structure, which is currently in use as electrolytes in Li ion batteries.

The development of experimental strategies to allow structural property correlations in optical materials through solid state NMR, EPR and photoluminescence, has proven effective in assisting the choice and fabrication of glass compositions with optimised properties.

Studies on rare earth doped fluorophosphate glasses and glass ceramics, carried out by the team led by Andrea S. S. De Camargo and H. Eckert at IFSC/USP showed that parameters such as absorption and emission cross sections, excited state lifetimes and quantum efficiencies can be tailored by controlling the chemical environment of the active rare earth ions [3] .

The Araraquara team led by Marcelo Nalin, together with the centre in LAVAL, carries out top-notch research on glasses and glass ceramics for applications such as optical thermometry, waveguiding, and solar light harvesting.

Recently, promising advances have been made on the fabrication of glasses exhibiting combined magnetic and optical responses [4] .

Among its future perspectives, CeRTEV aims to strengthen the incorporation of machine learning approaches to design optimised compositions. Traditionally, inefficient trial and error had to be used to find the right glass composition for a particular application. However, this is progressively changing as results from 60 years of glass science have been organised in a comprehensive database (SciGlass), which can be further expanded with molecular dynamics simulations.

Highly effective artificial intelligence methods as neural networks have been developed for mining this database, and this approach of machine-learning can be used to train the neural networks for predicting glass compositions (known or unknown) that exhibit key applicationrelevant physical properties.

Researchers at CeRTEV have successfully tested this approach for a combination of glass transition temperature and refractive index. The machine-learning tool came up with specific suggestions for glass compositions which were experimentally tested with encouraging initial results (to be published).

With these new developments the ultimate glassmaker’s dream of designing adequate glass compositions for given applications, is within reach! In 2022 we find ourselves on the threshold of an exciting and challenging decade of research and innovation in glass science.

� Schematic diagram of CeRTEV’s research agenda and responsible researchers.

References:

[1] Diretório dos Grupos de Pesquisa no Brasil Lattes. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), http://lattes.cnpq. br/web/dgp. [2] L.V. D. Gammond, H. Auer, R. M. da Silva, A. Zeidler, J. F. Ortiz-Mosquera, A. M. Nieto-Munoz, A. C. M. Rodrigues, I. D. A. Silva, H. Eckert, C. J. Benmore, P. S. Salmon, Structure of crystalline and amorphous materials in the NASICON system Na1+xAlxGe2-x(PO4) (3), J. Chem. Phys. 155 (2021), DOI: 10.1063/5.0049399. [3] M. Oliveira, T. Uesbeck, T. S. Gonçalves, C. J. Magon, A. S. S. de Camargo, H. Eckert, Network Structure and Rare-earth Ion Local Environments in fluorophosphate photonic glasses Studied by solid state NMR and EPR, J. Phys. Chem. C. 119 (2015) 24574-24587. DOI: 10.1021/acs. jpcc.5b08088. [4] D. F. Franco, Y. Ledemi, W. Correr, S. Morency, C. R. M. Afonsoc, S. H. Messaddeq, Y. Messaddeq, M. Nalin, Magneto-optical borogermanate glasses and fibers containing Tb3+, Scientific Reports 11 (2021). DOI: 10.1038/s41598021-89375-1.

*São Carlos Institute of Physics, University of São Paulo, IFSC/USP, Brazil https://www2.ifsc.usp.br/english/

CeRTEV – Center for Research, Technology and Education in Vitreous Materials, São Carlos, SP, Brazil https://www.certev.ufscar.br/en