Detailed Product Description

 Physical performance

Coefficient of mean linear thermal expansion(20,300)    3.3±0.1 10^-6K^-1

Transformation temperature                                         525±15

Softening point                                                           820±10

Working point                                                            1260±20

Density at 20                                                             2.23±0.02g/cm³

Mean thermal conductivity(20-100)                              1.2w/m²k

Refractive index                                                          0.92

Main Composition

SiO_{2                      81}

B₂O_{3                     13}

Na₂O+K₂O        4

Al₂O_{3                     2}

Chemical Property

Hydrolytic resistance at 98          ISO719-HGB 1

Hydrolytic resistance at 121        ISO720-HGA 1

Acid resistance Class                 ISO1776-First Class