TC07: Crystallisation & GCs

The strategy of TC07 is based on the following topics: -new properties and new applications of multi-component glass-ceramics; -fundamental studies of the kinetics mechanisms of nucleation and overall crystallization (e.g. surface versus internal crystallization).

To understand from both theoretical and experimental points of view the fundamental aspects that govern crystal nucleation and growth in glasses; and to foster collaboration between academic, governmental, and industrial researchers to develop, characterize, and optimize existing and novel glass-ceramics and their processing with focus on multi-component systems.

Activities 2020/21


Due to Covid-19 pandemic constrains, no conference activities and business meetings could be held during the last two years. However, TC07 members were involved in several conference preparation activities. S. Zhou serviced as lead organizer of Symposium 11 Luminescence properties and photonic applications of glass at the ICG Annual Meeting 2021 in Seoul and T. Honma has been engaged as lead organizer of Symposium 03 Crystallization, glass-ceramics and glasses with nano-crystals. L. Cormier organized the TC7 Symposium “Crystallization 2020” in Paris as conference chair. Together with M. Compte, he also edited the special issue “Crystallization in glasses and liquids” of the Journal of Non-Crystalline Solids, gathering some of the planned symposium contributions. Several TC07 members were among the authors (J. Deubener, R. Hill, T. Honma, T. Kokubo (former member), T. Komatsu, R. Müller, M.J. Pascual).

TC07 Round Robin Glass

Other TC07 activities were focussed on cooperative efforts to better interlock the strong and diverse activities of its academic and industry members. This initiative was already started-off 2019 at the business meeting in Boston and was further continued via email correspondence in 2020 and 2021. It became clear that defining a round-robin glass for testing of key metric(s) for crystallization studies should be the next step to go. Leveraging the industrial-scale melting laboratories available to some TC07 members could yield kg-scale melts of desired compositions, sufficient to provide all interested researchers with sufficient material for multiple tests on the exact same glass. Meanwhile, the vast majority of TC07 members expressed their interest in taking part in such a round-robin activity.

To attract long lasting and broad interest, the round-robin glass should also allow to study aspects related to the common research topics of TC07. Email discussions among TC07 members in 2019 revealed (a) Non-stoichiometric crystals, including solid solutions, their associated compo­sitions, and related kinetic processes and metastable crystals, (b) Residual glass composition and amount, (c) TTT- diagrams, and (d) Phase separation and associated crystallization processes to be the most interesting common topics. Further, the round-robin glass must be easy meltable in large scales and must not interfere with current confidential industrial research interests. TC07 members discussed several candidates among which sodium borosilicate glasses are currently under debate. Several such glasses have been melted and tested with DSC. Finding an optimum combination of sufficient crystallization and liquid phase separation tendency, as desired for testing of key metric(s) for crystallization studies, turned out to be a challenge.

Other Cooperations / Publications

E.D. Zanotto and V. Fokin published a series of common papers on the effects of structural relaxation on nucleation kinetics:
– L. R. Rodrigues et al. Relaxation effect on crystal nucleation in a glass unveiled by experimental,
numerical, and analytical approaches, Acta Materialia 223 (2022) 117458;
– V. M. Fokin et al. Effect of structural relaxation on crystal nucleation in glasses,
Acta Materialia 203 (2021)  116472
– J. W.P. Schmelzer et al. Effects of Glass Transition and Structural Relaxation on Crystal Nucleation:
Theoretical Description and Model Analysis, Entropy (2020), 22, 1098;
– L. R. Rodrigues et al. Effect of structural relaxation on crystal nucleation in a soda-lime-silica glass,
J Am Ceram Soc. 2021;104:3212–3223
J. Deubener and R. Müller continued common research projects on the effects of volatiles in glass
– T. Welter et al. Hydrogen Permeation Through Glass, Frontiers in Materials 1/2020;
– R. Balzer et al. Water in Alkali Aluminosilicate Glasses, Frontiers in Materials 5/2020;
– Kiefer et al. Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses,
Frontiers in Materials 8/2020;
– Waurischk et al. Crack Growth in Hydrous Soda-Lime Silicate Glass, Frontiers in Materials 3/2020;
– Waurischk et al. Crack growth in borate and silicate glasses: Stress-corrosion susceptibility and
hydrolytic resistance, JNS 551 (2021) 120414;
– Waurischk et al. Vacuum Crack Growth in Alkali Silicate Glasses, JNS 572 (2021) 121094

L. Cormier and S. Zhou co-authored a paper about transition metals as optically active dopants in glass-ceramics (Appl. Phys. Lett. 116, 26210503, 2020).

Future TC07 Activities

J. Deubener organizes the upcoming ICG2022 Congress in Berlin as Congress President. TC07 is planning to organize session P2 Crystallization and Glass-Ceramics of Symposium III Glass Physics, Properties and Characterization. If not earlier, a final decision on the intended TC07 round-robin glass is planned to be made at the occasion of the TC07 business meeting in Berlin.

Activities 2019

TC07 members were engaged at ICG Boston as session organizers and gave invited talks. TC07 organized session I-8 (M. Davis, R. Müller; Invited talks: T. Komatsu, I. Mitra), E. D. Zanotto co-organized session II-2 (Invited talk: J. Deubener), J. Deubener organized session IV-1, and R. Hill symposium VI. The session Arun K. Varshneya Festschrift was supported by W. Höland, and E. D. Zanotto with invited talks.

During the business meeting at ICG Boston, TC07 members intensively discussed how to better interlock the strong and diverse activities of its academic and industry members. Following previous informal questionnaires, short presentations were given, and promising strategies were discussed. Inspired by the positive response to the above-mentioned joint publication, TC07 members decided to define a round-robin glass for testing of key metric(s) for crystalli­zation studies as the next step to go. Leveraging the industrial-scale melting laboratories available to some members of TC07 could yield kg-scale melts of desired compositions, sufficient to provide all interested researchers with enough material for multiple tests on the exact same glass.

In 2019, TC07 members continued their manifold activities in teaching, cooperative research and organizing conferences. J. Deubener taught at the 11th Montpellier Summer School organized by TC23 and M. J. Pascual Francisco participated as teacher in the First North American Summer School on Photonic Materials (NASSPM) organized by TC20. W. Höland and M. Rampf submitted a book chapter “Glass-ceramics for dental restorations” to be included in: K. Pawelec (ed.), “Bone repair biomaterials: Regeneration and clinical aspects” (2nd ed.). Together with G.H. Beall, W. Höland launched the 3rd edition (!) of the textbook: Glass-ceramic technology. W. Höland also gave an invited talk at Bio-4, Toronto, Canada, July 2019 (Symposium Delbert Day).

TC07 members were engaged in organizing conferences unfortunately cancelled due to the COVID-19 crisis. L. Cormier organized the symposium “Crystallization2020” ( ) and J. Deube­ner, I. Mitra, and L. Cormier, organized a session at DGG-USTV 2020 in Orleans (https://ustv-dgg-2020. Last, but not least, based on their continuous cooperation, TC07 members published 5 joint papers on crystallizing bio glasses (with TC04), sodium ion conductive glasseshydrogen diffusivity in aluminosilicate glasses, hydrous soda-lime-silica and silicoborate glasses.

Shifeng Zhou (first left) and Robert Hill (second right) were honoured with the “2018 V. Gottardi Prize” and the “Varshneya Glass Technology Lec­ture”, respectively, at ICG Boston. (Photographed at the joint TC07 dinner celebrating the best TC web page prize 2018)

The joint TC07 paper “Updated definition of glass-ceramics” was honoured by the Journal of Non-Crystalline Solids with “The 2018 Most downloaded article Award”.

Activities 2018

Definition of glass-ceramics updated

Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads

“Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%”.

Schematic description of the conversion of a glass into a glass-ceramic. The critical cooling rate is qc = (TL – TN) / δt with TL = liquidus temperature, and TN = “nose temperature” (= temperature at which the time δt to achieve a crystal fraction of 10−6 is shortest). Glass formation by melt-quenching takes place for q ≥ qc. “Uncontrolled” spontaneous crystallization occurs for q < qc. The glass-ceramic A is obtained during cooling, whereas glass-ceramics B and C are converted by single and double-stage heat-treatments, respectively.

Get the full article here.

Teaching glass-ceramics

TC07 members lectured on “Controlled crystallization of glasses – from transformation kinetics to glass-ceramics” at the 10th ICG Summer School in Montpellier.

Main ideas of the course were included in the book  “Teaching glass better” published by ICG in 2018. The chapter on crystallization and GCs aims in sketching the theory of nucleation and crystal growth and sheds light on the variety of experimental methods to determine kinetically relevant parameters. Classical techniques to measure nucleation and growth rates using double-stage heat treatments and image analysis are introduced and flanked by advanced calorimetric methods and high temperature X-ray diffractometry. The requirements of a controlled crystallization process for glass-ceramics manufacturing are the prime focus of the chapter and the common strategy in industry of splitting the nucleation and functionality tasks between two or more phases is highlighted for two types of glass-ceramic products.

From the chapter

“Tammann rate curves are the representation of the temperature dependence of the steady state nucleation rate I0 and the size independent growth rate U0 in a common diagram. Besides homogeneous nucleation (HOM), a nucleation rate curve for each type of external active site has to be considered (HET1, HET2, etc.). Depending on the chemical system under consideration U0 and I0 curves are more or less overlapping. The liquid-to-crystal transformation proceeds steadily in the temperature range of the overlap of both rate curves.”

Tammann rate curve representations: (a) small (top) vs. large (bottom) overlap; (b) plus heterogeneous nucleation at external sites. Shaded area indicates overlap range.

Get the full book here.

Activities 2017

12th International Symposium on Crystallization in Glasses and Liquids (2017)

The 12th International Symposium on Crystallization in Glasses and Liquids (Crystallization 2017) was celebrated in the historic city of Segovia, Spain. The conference chairs were M.J. Pascual and A. Durán. The home page of the event is still available here. The conference venue was the Auditorium in the Parador de Segovia. The Spanish Society of Ceramics and Glass (SECV) had the pleasure and honour to host this conference, which is the twelfth in a series. Previous versions have been held in

Nagaoka, Japan 2015 (T. Komatsu, A. Sakamoto)
Goslar, Germany 2012 (J. Deubener)
Iguaçu Falls, Brazil 2009 (E.D. Zanotto)
Jackson Hole, Wyoming U.S.A. 2006 (M.J. Davis)
Sheffield, England 2003 (P.F. James)
Vaduz, Liechtenstein 2000 (W. Höland)
Florianopólis, Brazil 1996 (E.D. Zanotto)

Over the years, these bi- or triennial meetings have established a strong international reputation for disseminating the state-of-the-art in crystallization research, from fundamental aspects to innovative glass-ceramic products. The Segovia meeting covered the areas of simulation and theory, formation, structure, properties, and applications of crystallized glasses presented in 57 lectures (including 11 invited talks) and 76 posters. In particular,  participants from nineteen different countries found excellent opportunities for facilitating discussion on:

Fundamental approaches to nucleation and crystal growth (the interplay of theory, modelling and experiment)
Experimental studies (compositional and structural influences)
Advanced methods, techniques and characterization tools (in-situ, real time)
Role of nucleation agents (halogens, rare-earth and transition-metal oxides, noble metals)
Properties of glass-ceramics (thermal, mechanical, electrical, optical, chemical)
Microstructure/property relationships in glass-ceramics (strength, transparency, chemical resistance)
Novel processing techniques (laser sintering, sol-gel, field-induced nucleation…)
Commercial and new glass-ceramic applications (appliances, armour, bio-medical, dental, optical, seals)
Crystallization phenomena in related materials (metallic glasses, polymer glasses, natural glasses)

The invited paper were given by:

C. Rüssel, Otto Schott Institute, Jena University (Germany)
J.W. P. Schmelzer, Rostock University (Germany)
A.S. Abyzov, NSC Kharkov Institute of Physics and Technology (Ukraine)
W. Höland, Ivoclar Vivadent AG (Liechtenstein)
Q. Jianrong, Zhejiang University (China)
H. Jain, Lehigh University (USA)
F. Serbena, UEPG (Brazil)
C. Siligardi, DIEF, University of Modena and Reggio Emilia (Italy)
T. Honma, Nagaoka University of Technology (Japan)
M. Allix, CEMHTI laboratory (France)
A. de Pablos-Martín, IMWS, Halle (Germany)

Two oral presentations and four posters presentations were awarded with a certificate and a gift (100 €) to presenters below 40 years old. The oral awards went to Susanne Krüger from Clausthal University (Germany) for her presentation “How to take into account the stochastic nature of nucleation in constructing a time-temperature-transformation diagram?” and Mariona Tarragó from Barcelona University (Spain) for her presentation “Simulation of vitrification of sewage sludge using a Ca-doped basalt”. The four posters awards went to Mikiya Kotava (Japan), Carsten Blaess (Germany), Tina Waurischk (Germany) and Laura Briese (Germany).

Awardees S. Krüger (centre-left) and M. Tarragó (centre-right) with the conference chairs M.J. Pascual (right) and A. Durán (left)

The excursion led through the Royal Glass Factory of La Granja National Centre of Glass and La Granja Gardens.
The Symposium was supported by:

Fundación Centro Nacional del Vidrio (FCNV, La Granja)
Erich Netzsch GmbH & Co. Holding KG
Segovia Convention Bureau

Topical issues edited by TC07

TC07 aims in publishing jointly research activities in electronic and print media.  The list shows finalized special issues on crystallization and GCs (guest editors are indicated in brackets).

Journal of Non-Crystalline Solids, Volume 501, 2018 (M.J Pascual, A Durán)
“Nucleation and Crystallization of Glasses and Glass-Ceramics” Frontiers Media SA, 2017 (W. Höland, J. Deubener)
MRS Bulletin, Volume 42, Issue 3, 2017 (M.J. Davis, E.D. Zanotto)
Journal of Non-Crystalline Solids, Volume 384, 2014 (J. Deubener)
Journal of Non-Crystalline Solids, Volume 356, Issues 52-54, 2010 (V.R. Mastelaro, M.J. Davis, E.D. Zanotto)
Am. Ceram. Soc., CD-ROM 2009, ISBN 978-0-470-09732-8 (M.J. Davis)
Phys. Chem. Glasses 45, 2004 and Glass Technol. 45, 2004  (P.F. James)
Glastech. Ber. Glass Sci. Technol. 73 C1, 2000 (W. Höland)
Journal of Non-Crystalline Solids, Volume 219, 1997 (E.D. Zanotto)

TC07 group

From left to right: Wolfram Höland,  María Jesús Pascual,  Signo Nakane, Joachim Deubener, Tsuyoshi Honma, Edgar Zanotto, Mark Davis, Ina Mitra, Shifeng Zhou, Ralf Müller, Takayuki Komatsu, Philippe Pradeau and Markus Rampf (Foto taken at the  Parador de Segovia, 2017).

Committee Members

Allix, Mathieu
Budd, Michael
Cormier, Laurent
Deubener, Joachim
Fokin, Vladimir
Hill, Robert
Höland, Wolfram
Honma, Tsuyoshi
Maeda, Kai
Mitra, Ina
Müller, Ralf Committee Position: Chair
Nakane, Shingo
Pascual, Maria Committee Position: Vice Chair
Pradeau, Philippe
Prado, Miguel Oscar
Rampf, Markus
Zanotto, Edgar
Zhou, Shifeng

Committee Contact Details

TC07: Crystallisation & GCs
Schott North America