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Nonlinear Variation of Refractive Index of Vitreous Silica with Pressure to 7 Kbars
Author(s) -
VEDAM K.,
SCHMIDT E. D. D.,
ROY RUSTUM
Publication year - 1966
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1966.tb13157.x
Subject(s) - refractive index , materials science , hydrostatic pressure , optics , hysteresis , hydrostatic equilibrium , photoelasticity , allowance (engineering) , linearity , composite material , range (aeronautics) , thermodynamics , condensed matter physics , optoelectronics , physics , quantum mechanics , mechanical engineering , engineering , solid mechanics
The variation of refractive index of vitreous silica with purely hydrostatic pressure to 7 kbars was determined from the shift of the localized interference fringes across the specimen kept in an optical pressure bomb. Allowance for the change in the thickness of the specimen was made with the help of Murnaghan's finite‐strain theory and the recently determined third‐order elastic constants. The refractive index for λ 5893 A increases linearly with pressure with a slope of 9.2 × 10 −4 /kbar up to 4 kbars; thereafter it increases nonlinearly. The increase in the refractive index, however, is linear with respect to the Lagrangian strain in the range investigated, except for a slight tendency for departure from linearity at the highest pressures. No hysteresis effects caused by permanent densification were noted. The results are interpreted in the light of Mueller's theory of photoelasticity of amorphous solids.