Glass - Back to the Future!



Presenting Author:
Atsunobu Masuno
<masuno@hirosaki-u-ac-jp>

article posted 2 Apr 2016


Atsunobu Masuno Dr. Atsunobu Masuno was born July 17, 1975 in Osaka, Japan. He received the Bachelor of Science in Chemistry in 1999, the Master of Science in Chemistry in 2001, and the Doctor of Science in Chemistry in 2004 from Kyoto University. He was a postdoc researcher in 2004?2005 in Kyoto University and a researcher in Japan Aerospace Exploration Agency in 2006. He was a research associate at the University of Tokyo from 2007 until 2016 and is at present an associate professor at Hirosaki University.






Functional oxide glasses prepared by a levitation technique

Atsunobu Masuno
Hirosaki University


Containerless processing, which enables a melt to be levitated in air, prevents the melt from crystallization at the boundary between the melt and a container wall. Accordingly, deeper undercooling can be realized and materials with a low glass forming ability are often vitrified. Some binary systems, such as Al2O3-based, TiO2- based, Nb2O5-based, WO3-based, Ta2O5-based glasses, have been vitrified in bulk form without using any network-former oxides by containerless processing. Among them, TiO2-based, and Nb2O5-based glasses have attracted much attention since the refractive index n is quite high (n ≈ 2.3) and the wavelength dispersion is rather low in visible range. The high refractive index n > 2.0 with low wavelength dispersion glass is a key optical component such as thinner lens for digital camera of smart phones, and solid immersion lens for next-generation optical disk system. Furthermore, the structural analyses by using X-ray and neutron diffraction and reverse Monte-Calro simulation, and molecular dynamics simulation revealed that the glass structures of the TiO2-based and Nb2O5-based glasses were quite different from those of the conventional oxide glasses. The high oxygen packing density causing the high refractive index is realized in these new glasses. Recently, new glass systems with strong mechanical properties have been obtained. Al2O3-Ta2O5 glasses have a very high elastic modulus and Al2O3-SiO2 glasses shows crack-resistant behaviors.