Shanghai Institute Of Optics And Precision Machinery (SIPM) Makes Progress in Studying The Structure And Properties Of Aluminum Phosphate Glass

Recently, a team of researcher Lili Hu from the Laboratory of High Power Laser Unit Technology, Shanghai Institute of Optics and Precision Machinery (SIPM), Chinese Academy of Sciences (CAS), has adopted a method combining experiments, molecular dynamics simulations, and Quantitative Structure-Property Relationship (QSPR) analysis to study aluminum phosphate glasses, and the related research results have been published in the Journal of the American Ceramic Journal of the American Ceramic Society.)
Currently, aluminum phosphate glasses have a wide range of applications in many fields, including biomedical materials, optical components, sealing materials and nuclear waste curing. The short-range structure of aluminum phosphate glasses has been studied more by means of experimental techniques, but the relationship between its properties and the medium-range structure is still unclear. And molecular dynamics simulations have become an effective tool for the study, playing an increasingly important role in revealing the structural origin of glass properties.
In this study, the researchers combined experimental and molecular dynamics simulation methods to investigate the effect of Al2O3 on the short-range and mid-range structures of aluminum phosphate glasses, and modeled their structural properties by the QSPR method. The accuracy of the simulation was verified by Raman, synchrotron radiation and other experimental results. The simulation results show that the P-O-P bonds present in the glass network are gradually replaced by P-O-Al bonds with the change of Al2O3 content, which plays an important role in the change of glass properties. Meanwhile, the long chains in the aluminum phosphate glasses are prone to form cyclic structures and are concentrated in the 4- to 20-membered rings. In addition, three different structural descriptors are utilized to model the QSPR and successfully correlate the experimental data with the simulation results, showing good model predictability. This method provides new ideas for predicting glass properties and designing glass components.
Progress of Shanghai Institute of Optics in studying the structure and properties of aluminum phosphate glasses
Fig. 1 Quantitative structure-property relationship model established by using (a) coordination number (CN), (b) Qn, and (c) ring size of aluminum phosphate glasses as structural inputs. From left to right, the structure descriptor Fnet is shown as a function of experimental density, hardness, glass transition temperature, and coefficient of thermal expansion, respectively.