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Residual birefringence of amorphous polymers for optical‐disk substrates
Author(s) -
Shindo Y.,
Saito M.,
Iwatsuka Y.,
Hasegawa H.
Publication year - 1991
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1991.070430414
Subject(s) - materials science , birefringence , epoxy , curing (chemistry) , residual stress , composite material , monomer , polymer , amorphous solid , annealing (glass) , raw material , thermosetting polymer , optics , crystallography , chemistry , organic chemistry , physics
Based on the Mueller matrix approach, we have successfully designed and constructed a highly sensitive instrument for measuring optical birefringence (LB) by using a polarization modulation method and phase‐sensitive technique. Our instrument can measure the retardation of a sample up to 10 −2 radian. Using this instrument, we have measured the residual birefringence of thermosetting resins, CR‐39 resin and epoxy resin, for opticaldisk substrates. CR‐39 resin results are summarized as follows: (1) Annealing is very effective in reducing LB of samples; (2) samples prepared from raw material 2 (monomer purity, 96%, oligomer, 4%) have smaller LB than those from raw material 1 (monomer purity, 99.9%); and (3) annealed samples prepared from 2 satisfy the requirement on LB to be used as optical‐disk substrates. For epoxy resin: (1) “Second curing” largely reduces LB of samples; (2) “slow cooling” is more effective in reducing LB of samples than “fast cooling;” (3) after the second curing, cutting does not induce any residual stress birefringence in samples; and (4) slow‐cooled samples have good optical properties to be used as optical disk substrates.