When from the quartz vitreous body for blank where the quartz vitreous body and OH

摘要

PROBLEM TO BE SOLVED: To provide a method for simply and accurately measuring the trace OH group concentration in a quartz glass body.;SOLUTION: In this OH group concentration measurement in quartz glass by infrared spectrophotometry, a measuring test piece and a blank test piece having facing two planes are manufactured respectively form a measuring quartz glass body and a blank quartz glass body having a known OH group content, and placed in an infrared spectrophotometer. An infrared ray having the wavelength in the range of about 2,500 nm-about 2,950 nm is allowed to enter vertically one plane of the facing two planes successively, and simultaneously an outgoing ray is detected from the other plane. This measuring method is characterized by determining the difference spectrum between outgoing ray spectrums of each test piece, selecting an OH group absorption peak in the wavelength of 2,720 nm, and calculating the OH group content rate from the peak height by using mathematical expression 1. [Expression 1] Csample=Cblank+ΔA/Lε×(MH+MO)/ρ×103 (Csample is the OH group concentration in the measuring test piece (wt.ppm), Cblank is the OH group concentration in the blank test piece (wt.ppm), ΔA is the peak height (ABS.), L is an optical path length (cm), ε is an absorption coefficient (1.mol-1.cm-1), MH is the atomic weight of hydrogen, MO is the atomic weight of oxygen, and ρ is the density of the quartz glass (g.cm-3).).;COPYRIGHT: (C)2001,JPO