This TC focuses on the nature of the vibrations in glasses and on the structural information that can be gained using inelastic spectroscopy techniques: infrared absorption, light scattering, neutron and X-ray scattering, etc, as well as numerical simulations of the vibrational properties. We will mainly concentrate on:
a) the origin of the boson peak and its relation with the end of acoustic branches
b) the understanding of the optic modes of oxide glasses and their relation to the structure, and
c) the contribution of inelastic spectroscopies to the characterization of the structural properties of technological glasses
A. Development of a database of Raman spectra
The platform is now existing, thanks to R. Down at the Arizona Univ., B. Lafuente at the SETI Institute (California), and their developer team.
Link to the platform : https://odr.io/ICGlassVib
B. Organization of two symposiums at ICG2109 in Boston (TC26 & TC03)
Structure of glass : Network Formers and Network Modifiers: The definition of glass forming ability is one of the first concept for which glass scientists tried to propose rules, essentially based on structural arguments. Since the first concept introduced by Zachariasen in 1932, and based on oxide glasses, the number of glass family increases a lot up to the chalcogenide, metallic, organic, spin glasses. How the Zachariasen concept of network formers, network modifiers, intermediate role, can survey in these others glasses systems? In this session, we encourage submission of abstracts whose purpose is to investigate the binding or depolymerizing role of the glass constituents, in order to motivate discussions between the scientific communities of oxide, chalcogenide, and metallic glasses.
Glass and Melt: Macroscopic Properties and Structure of Melt at High Temperature: The links between a glass and its liquid counterpart are complex but fundamental for the development of new vitreous or crystalline materials. In this session, we encourage presentations on global studies between glass and liquid at high temperature, investigations that will relate the structural or macroscopic properties of the liquid to that of the glass.
C. TC26 Meeting at ICG2019 in Boston
The discussion was focused on issues related to the creation of the Raman Database.
Present : G. Anderson, D. Neuville, E. Kamistsos, D. Moncke, B. Rufflé, M. Cicconi, K. Burov, D. De Ligny, and B. Hehlen (Chair)
TC26 Meeting at the “15th Physics of non-Crystalline Materials Congress” in St Malo-France, Sunday 9th july 2018
TC26 Meeting at the “ICG Annual meeting” in Yokohama –Japan, Sunday 23th September 2018.
TC 26 Current action:
Project of creation of a web platform (RODGlass) in order to upload/download Raman spectra on glasses to/from the existing Raman Open-source Database (ROD) : http://solsa.crystallography.net/rod/index.php. The aim of the project is to provide glass scientists a database of Raman spectra. In the first version of the platform, the Raman data should be published ones. The first action of TC26 was to define the information file attached to each spectrum. The file gathers information such as the samples source, the spectrometer, the sample environment, temperature, pressure, thermal history, the reference of the article,… and for sake of simplicity for users, it will have the form of an excel file.
Plan for 2019 :
TC Meeting in ICG2019 in Boston (US). The discussion will be mainly focused on the development of the RODGlass platform :
- Development of the code source which will convert the “excel” Information File into the “ROD” format in order to upload the Raman spectra on the ROD database.
- Defining a list of Raman spectra providers who would be interested to upload their data to the ROD database.
- Starting uploading Raman spectra on the ROD.
- In parallel (mid-term action) we should develop a webpage (RODGlass platform) for automatic uploadings. The platform should also allow making searches on the ROD database in order to download spectra. The use of these spectra will be submitted to citations, as for articles.
Follow up of the actions of TC26
2019 : Raman database online: https://odr.io/ICGlassVib
2018 : Creation of a Raman database on glasses (in progress)
2018 : Contribution to the Book “Teaching Glass Better: 10th anniversary of the ICG summer School”: Light scattering by atomic vibrations
2015: Expert meeting on vibrations at PNCS conference in Niagara Falls, USA (22th septembre 2015)
2014 : Contribution to the book “Making Glass Better”: Optic modes in simples glasses & Origin of the boson peak
The conclusions of the expert meeting held in 2010 in Montpellier and gathering the members of TC26 have been summarized in the book “Making Glass Better 2”. The section concerning “vibrations and glass structure” has been organized as follows:
- Experts’ abstracts and main scientific interests. This part summarizes the main scientific contributions of the lecturers in the field over the last decades.
- Optic modes in oxide glasses. This part summarizes the discussion on the origin of the optic modes of glasses. experimental and simulation results during the last decades lead to a rather accurate description of the vibrations in simple oxide glasses, such as glass former or binary systems. Efforts should now be directed towards more complex systems, for example aluminosilicates, borosilicates, etc. and glasses with one or more alkali cations.
- Origin of the boson peak: the situation is here much more controversial. We extracted from the highly disputed discussion the progress which had the agreement of a large majority.
Finally, the section focused on expected breakthroughs in the field.
de Ligny, Dominique
Hehlen, Bernard Committee Position: Chair
Kamitsos, Efstratios (Prof)
Moncke, Doris (Dr)
Committee Contact Details
TC26: Structure & Vibrations
Prof Bernard Hehlen
University of Montpellier