Foreword

Glasses are ubiquitous and all-pervading in modern life, and their importance cannot be understated. We are all familiar with glass in windows and probably look through glass multiple times a day. Window glass can be easily processed to give an extremely high transparency product, which is strong and optically flat. This ease of processability is also exploited for construction of fibre optic cables, originally used to transmit data at high speed across oceans, but we are now seeing fibre optic communication arriving at our doorsteps. Again, the high levels of processability coupled with excellent transmissibility in the particular part of the required spectrum are key to their success. Glasses can also be processed into fibreglass to make extremely high volumes of high-quality, fire-retardant insulation. These are just some of the areas of use of glasses.

Considering the widespread use, glasses in general are still relatively poorly understood in terms of their atomic structure and how this relates to the properties found in the end products. We have measurement methods available to probe glasses at the bulk scale and then methods to determine local environments around specific atoms. However, glasses are very polymeric in nature and structure, and many of the properties found in glasses come from this medium range polymeric order, which is difficult to analyse in detail.

By weight and also volume, silicate-based glasses are by far the most common glasses in use. However, there are other families of glasses that have unusual properties that can be exploited, and these are the phosphate and borate families of glasses which are covered in this book. In particular, one of the unique properties of these glasses is that they are degradable, and this makes them of great interest in biomedicine. Their ability to dissolve in body fluids makes them of great interest for use in wound dressings or for drug delivery, allowing them to degrade after their action has been performed.

This work brings together leading experts in the field to cover the fundamental properties of these materials, such as the current understanding of the relationship between their atomic structure and physical properties, and then goes on to chapters discussing their potential applications. Perhaps one of the most interesting aspects is their synthesis via sol–gel routes. This methodology opens up previously unachievable glass compositions, thus expanding their potential use. Sol-gels also offer some interesting processing routes for the synthesis of things like nanoparticles and nanofibres. Finally, one of the other areas covered is their application in biophotonics. Phosphates have unique optical properties, such as broad-spectrum transmissivity; these have been difficult to exploit in conventional areas such as fibre optics because of their solubility, but they can potentially be utilised in biomedicine, where the device lifetime can be short term. Overall, this is an excellent resource, bringing together the current knowledge in the fields of phosphate and borate glasses, and will, I am sure, be widely used by researchers in the field and also in other disciplines seeking to exploit the unique properties of these glasses.

Professor Jonathan Knowles, BSc, PhD, FIMMM, FRSC, CEng, FAIMBE

Professor of Biomaterials Science

Division of Biomaterials and Tissue Engineering

UCL Eastman Dental Institute