Temperature and pressure dependence of elastic properties of heavy-metal flouride glasses

• Main Author: 陳家和
• Other Authors: 華魯根
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/46400058210795773358

碩士 === 輔仁大學 === 物理學系 === 88 === When light signal transmits in a fiber, it will affect by the change of pressure, temperature and some kinds of environmental influences. Then the signal will degrade. Consequently, the study of pressure and temperature dependence of elastic properties of glassy materials becomes important. In this paper, temperature and pressure dependence of ultrasonic velocities (both longitude and transverse) in two ZBLAN glasses were determined by ultrasonic pulse-echo technique. The experimental results provide the complete set of components of the second-order and third-order elastic constants. The second-order elastic constants are of central importance in any study of the vibrational properties of a solid because they determine the slope of the dispersion curves at long-wavelength limit. The third-order elastic constants are of interest because they characterize the an-harmonic properties, that is the non-linearity of the atomic forces with atomic displacements.