Transmission factor with of the wall thickness 1mm where ultraviolet ray absorption glass and the glass

摘要

PROBLEM TO BE SOLVED: To provide a glass tube for a fluorescent lamp which has enough resistance against solarization by UV rays and which does not transmit harmful UV rays.;SOLUTION: The glass consists of borosilicate glass containing, by mass%, 0.001 to 0.05% Fe2O3, 0.05 to 3% Sb2O3 and 0.01 to 3% ZrO2 and having 46 to 57×10-7/°C average coefficient of linear expansion in the temperature range from 50°C to the glass transition temperature (Tg). The transmittance of the glass with 1 mm thickness for the light at 253.7 mm wavelength is ≤1%, and the deterioration degree by specified UV irradiation test is ≤3%.;COPYRIGHT: (C)2002,JPO