Glass - Back to the Future!

Presenting Author:
Michela Buscemi

article posted 26 May 2016

Michela Buscemi is a PhD student at University of Bath, UK.
She graduated in Chemistry in 2013 and Chemical Engineering in 2015 from the University of Catania.

Structure of glassy B2O3-GeO2 by using neutron diffraction with isotope substitution

Michela Buscemi*1, Anita Zeidler1, Philip S. Salmon1, G S. Moody1, Alex C. Hannon2
1Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom 2ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom

The B2O3-GeO2 system is one of the few oxide glass-forming materials that comprises solely network-forming cations, and the local motifs in the pure component B2O3and GeO2 glasses are rather different, i.e. BO3 planar triangles versus GeO4 tetrahedra, respectively. The B2O3-GeO2 system is therefore a prototype for investigating the effect of mixing these network forming ions. For instance, a tendency for chemical ordering will lead to a preference for B-O-Ge linkages, while the converse will favour B-O-B and Ge-O-Ge linkages and hence a tendency for phase separation. It is this competition that will control the network topology, and which can be exploited by the addition of modifiers to make materials with technological applications, e.g. multicomponent borogermanate glasses have been widely used as nonlinear optical materials [1].

Here the composition dependent structure of the (B2O3)x(GeO2)1-x (x=0.2, 0.3, 0.4, 0.5, 0.6, 0.8) system was studied with neutron diffraction. The neutron diffraction with isotopic substitution method (NDIS) was used to study the eutectic (B2O3)0.6(GeO2)0.4. Information about the coordination environments of both the Ge and B atoms at the nearest-neighbour distances and beyond is presented.

[1] Lee S K, Kim H N, Lee B H, Kim H-I and Kim E J 2010 J Phys Chem B 114 412