Determination of refractive indices and linear coefficients of thermal expansion of silicate glasses containing titanium oxides

Yoshinao Kobayashi, Taiichi Shimizu, Shigekazu Miyashita, Rie Endo, Masahiro Susa

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


A growing attention has been paid to development of 'athermal glass', which is a material showing no temperature dependence in its optical path length and is expected to be used in optical devices for the optical fibre transmission system. The athermal characteristic is usually evaluated using the dependence of optical path length (S ) on temperature (T ) expressed by the following equation: 1/l dS/dT=nα+dn/dT where l, n and α are the geometrical length, refractive index and linear coefficient of thermal expansion of a sample, respectively. In the present work, the refractive index and liner coefficient of thermal expansion have been determined for silicate glasses containing titanium oxides in the temperature range from room temperature to about 673 K, respectively, using ellipsometry and the apparatus with image analysis equipment. The values of nα and temperature coefficient of n ranged from 1.289×10-5 to 3.345×10-5 K -1 and from 0.270×10-5 to 1.467×10 -5 K-1, respectively, depending on the glass composition. As a consequence, it has been found that additions of titanium oxides do not have good effects on the athermal characteristic. However, only 80SiO 2-5TiO2-15Na2O (on a mole basis) glass has shown almost the same degree of athermal characteristic as SiO2 glass, and it is suggested that 80SiO2-5TiO2-15Na 2O glass has more advantages in practice due to its lower melting temperature than SiO2.

Original languageEnglish
Pages (from-to)186-192
Number of pages7
JournalISIJ International
Issue number2
Publication statusPublished - 2011
Externally publishedYes


  • Athermal glass
  • Glass technology
  • Linear coefficient of thermal
  • Optical property
  • Refractive index

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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