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Research and Development
Glass Materials
*Low expansion crystallized glass/TCM
*New glass materials/XHK
*Hard glass with UV protection
*NVG green glass
*NVG blue glass
*IR transparent glass
Thin Film Technology
Multilayer Thin Film Filter for Optical Communications


Okamoto Glass Co., Ltd. New Glass Materials/XHK
  • Has a low coefficient of thermal expansion and high thermal shock strength
  • Has a high glass transition point, enabling use at higher temperatures
  • Can precisely copy the mold
  • Does not require thermal processing

Properties of XHK
Density(kg/m3) 2.5×103
Thermal expansion coeff(×10-7/K) 34
Glass transition point(degreeC) 680
Deformation point(degreeC) 770
Strain point(degreeC) 643
Annealing point(degreeC) 697
Softening point(degreeC) 930
Thermal shock temp.difference(degreeC) 210
Abraded strength(MPa) 133
Vickers hardness(Hv) 610
Young's modulus(GPa) 81
Poisson ratio 0.24
Thermal conductivity(W/m・K) 1.09
Specific heat(J/kg・K) 783
Refractive index(Nd) 1.515
Water resistance(Na2Omg)* 0.05
Dielectric constant 1MHz 5.6
100MHz 5.5
Dielectric loss 1MHz 0.002
100MHz 0.003
* JIS R-3502 Powder Method

The data shown in this table are based on our measurement of the materials and do not constitute a guarantee that the materials will have these properties.

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Okamoto Glass Co., Ltd.
info@okamoto-glass.co.jp