Thermal and crystallization kinetics of yttrium‐doped phosphate‐based glasses

• Published in: International journal of applied glass science 2020-01, Vol.11 (1), p.120-133
• Main Authors: Arafat, Abul, Samad, Sabrin A., Wadge, Matthew D., Islam, Md Towhidul, Lewis, Andrew L., Barney, Emma R., Ahmed, Ifty
• Format: Article
• Language: English
• Subjects: Activation energy; Biomedical materials; Crystal growth; Crystallization; crystallization kinetics; DSC; Glass; Molar volume; Morphology; Radiation therapy; Yttrium oxide; yttrium phosphate glass
• ISSN: 2041-1286; 2041-1294
• DOI: 10.1111/ijag.14163

Yttrium‐doped glasses have been utilized for biomedical applications such as radiotherapy, especially for liver cancer treatment. In this paper, the crystallization behavior of phosphate‐based glasses doped with yttrium (in the system 45P2O5–(30 − x) Na2O–25CaO–xY2O3—where x = 0, 1, 3 and 5) have been investigated via Differential Scanning Calorimetry (DSC) using nonisothermal technique at different heating rates (5°C, 10°C, 15°C and 20°C/min). The glass compositions were characterized via EDX, XRD, Density and Molar volume analysis. The Moynihan and Kissinger methods were used for the determination of glass transition activation energy (Eg) which decreased from 192 to 118 kJ/mol (Moynihan) and 183 to 113 kJ/mol (Kissinger) with increasing yttrium oxide content. Incorporation of 0 to 5 mol% Y2O3 revealed an approximate decrease of 71 kJ/mol (Ozawa and Augis) for onset crystallization (Ex) and 26 kJ/mol (Kissinger) for crystallization peak activation energies (Ec). Avrami index (n) value analyzed via Matusita–Sakka equation suggested a one‐dimensional crystal growth for the glasses investigated. SEM analysis explored the crystalline morphologies and revealed one‐dimensional needle‐like crystals. Overall, it was found that these glass formulations remained amorphous with up to 5 mol% Y2O3 addition with further increases in Y2O3 content resulting in significant crystallization.