Abstract: A glass composition which is reduced in the amount of residual bubbles and is produced using smaller amounts of an environmentally unfriendly component such as arsenic oxide and antimony oxide. This glass composition contains, in terms of mass %: 40-70% SiO2; 5-20% B2O3; 10-25% Al2O3; 0-10% MgO; 0-20% CaO; 0-20% SrO; 0-10% BaO; 0-0.5% Li2O; 0-1.0% Na2O; 0-1.5% K2O; and 0-1.5%, excluding 0%, Cl, Li2O+Na2O+K2O exceeding 0.06%. The glass composition can be produced suitably using, for example, a chloride as part of the raw glass materials.

Abstract: A glass composition which is reduced in the amount of residual bubbles and is produced using smaller amounts of an environmentally unfriendly component such as arsenic oxide and antimony oxide. This glass composition contains, in terms of mass %: 40-70% SiO2; 5-20% B2O3; 10.25% Al2O3; 0-10% MgO; 0-20% CaO; 0-20% SrO; 0-10% BaO; 0-0.5% Li2O; 0-1.0% Na2O; 0-1.5% K2O; and 0-1.5%, excluding 0%, Cl, Li2O+Na2O+K2O exceeding 0.06%. The glass composition can be produced suitably using, for example, a chloride as part of the raw glass materials.

Abstract: A glass composition which is reduced in the amount of residual bubbles and is produced using smaller amounts of an environmentally unfriendly component such as arsenic oxide and antimony oxide. This glass composition contains, in terms of mass %: 40-70% SiO2; 5-20% B2O3; 10.25% Al2O3; 0-10% MgO; 0-20% CaO; 0-20% SrO; 0-10% BaO; 0-0.5% Li2O; 0-1.0% Na2O; 0-1.5% K2O; and 0-1.5%, excluding 0%, Cl, Li2O+Na2O+K2O exceeding 0.06%. The glass composition can be produced suitably using, for example, a chloride as part of the raw glass materials.

Abstract: A glass composition which is reduced in the amount of residual bubbles and is produced using smaller amounts of an environmentally unfriendly component such as arsenic oxide and antimony oxide. This glass composition contains, in terms of mass %: 40-70% SiO2; 5-20% B2O3; 10-25% Al2O3; 0-10% MgO; 0-20% CaO; 0-20% SrO; 0-10% BaO; 0-0.5% Li2O; 0-1.0% Na2O; 0-1.5% K2O; and 0-1.5%, excluding 0%, Cl, Li2O+Na2O+K2O exceeding 0.06%. The glass composition can be produced suitably using, for example, a chloride as part of the raw glass materials.

Abstract: A glass composition which is reduced in the amount of residual bubbles and is produced using smaller amounts of an environmentally unfriendly component such as arsenic oxide and antimony oxide. This glass composition contains, in terms of mass %: 40-70% SiO2; 5-20% B2O3; 10-25% Al2O3; 0-10% MgO; 0-20% CaO; 0-20% SrO; 0-10% BaO; 0-0.5% Li2O; 0-1.0% Na2O; 0-1.5% K2O; and 0-1.5%, excluding 0%, Cl, Li2O+Na2O+K2O exceeding 0.06%. The glass composition can be produced suitably using, for example, a chloride as part of the raw glass materials.

Abstract: The present invention provides a glass composition that exhibits a fluorescence function and an optical amplification function in a wide wavelength range. This glass composition includes a bismuth oxide, a silicon oxide, an aluminum oxide, and a divalent metal oxide, and the glass composition emits fluorescence in an infrared wavelength region through irradiation of excitation light, with bismuth contained in the bismuth oxide functioning as a fluorescent source.

Abstract: The present invention provides a novel glass composition in which fluorescence derived from bismuth (Bi) is obtained and whose meltability is improved. The glass composition of the present invention includes bismuth oxide, Al2O3 and SiO2. SiO2 is a main component of glass network forming oxide included in the glass composition. The glass composition further includes at least one oxide selected from TiO2, GeO2, P2O5 and B2O3. A total content of SiO2, the at least one oxide, Y2O3 and lanthanide oxide is over 80 mol %. Bismuth included in the bismuth oxide functions as a luminous species. Upon irradiation of excitation light, the glass composition emits fluorescence in the infrared wavelength range.

Abstract: The present invention provides a glass composition that exerts an emission function or an optical amplification function in a wide wavelength range. The glass composition contains, bismuth oxide, aluminium oxide, and a glass network former, and a main component of the glass network former is germanium dioxide. Bismuth contained in bismuth oxide functions as an emission species and emits fluorescence in the infrared wavelength region by irradiation of excitation light. The glass composition may further contain a monovalent or divalent metal oxide.

Abstract: The present invention provides a glass composition that exhibits a fluorescence function and an optical amplification function in a wide wavelength range. This glass composition includes a bismuth oxide, an aluminum oxide, and a glass network former. The glass network former includes an oxide other than silicon oxides as its main component. The glass composition emits fluorescence in an infrared wavelength region through irradiation of excitation light, with bismuth contained in the bismuth oxide functioning as a fluorescent source. A preferable glass network former is B2O3 or P2O5. This glass composition further may contain a univalent or divalent metal oxide.

Abstract: The present invention provides a glass composition that exhibits a fluorescence function and an optical amplification function in a wide wavelength range. This glass composition includes a bismuth oxide, a silicon oxide, an aluminum oxide, and a divalent metal oxide, and the glass composition emits fluorescence in an infrared wavelength region through irradiation of excitation light, with bismuth contained in the bismuth oxide functioning as a fluorescent source.

Abstract: A glass article of the present invention has a rate of dissolution in an acidic liquid of from 10 to 100 nm/min in terms of etching rate in immersing in a 0.1% by weight 50° C. aqueous solution of hydrofluoric acid and an average linear thermal expansion coefficient of 70×10−7/° C. or higher as measured in the range of from −50° C. to 70° C., and the working temperature T4 (° C.) and the liquidus temperature TL (° C.) thereof satisfy the relationship: T4−TL≧−100° C.

Abstract: An optical wavelength conversion device comprising: a modulating signal generating unit for generating a modulating signal; an optical modulating unit for modulating input light by the modulating signal; and wavelength select means for extracting only a necessary component from an optical signal generated by the optical modulating unit. In the optical wavelength conversion device, the optical modulating unit may be an amplitude modulator or a phase modulator. The modulating signal may be an electrical signal or an optical signal. When the modulating signal is an optical signal, the optical signal consists preferably of light of a plurality of wavelength components.

Abstract: A glass article of the present invention has a rate of dissolution in an acidic liquid of from 10 to 100 nm/min in terms of etching rate in immersing in a 0.1% by weight 50° C. aqueous solution of hydrofluoric acid and an average linear thermal expansion coefficient of 70×10−7/° C. or higher as measured in the range of from −50° C. to 70° C., and the working temperature T4 (° C.) and the liquidus temperature TL (° C.) thereof satisfy the relationship: T4−TL≧−100° C.

Abstract: A glass composition is disclosed which has a high modulus of elasticity and a low density, i.e., has a high specific modulus. Also disclosed is an inexpensive glass composition which is suitable for use as an information recording medium substrate, for example, because it can be formed easily, is less apt to suffer devitrification, is suitable for mass production, and can be easily made to have high surface smoothness by polishing. The glass compositions comprise, in terms of mol %, 35 to 45% silicon dioxide (SiO2), 15 to 20% aluminum oxide (Al2O3), 3 to 10% lithium oxide (Li2O), 0.1 to 5% sodium oxide (Na2O), 15 to 30% magnesium oxide (MgO), 0 to 10% calcium oxide (CaO), 0 to 4% strontium oxide (SrO), 25 to 35% RO (MgO+CaO+SrO), 2 to 10% titanium dioxide (TiO2), 0.5 to 4% zirconium oxide (ZrO2), 4 to 12% TiO2+ZrO2, and 0 to 4% yttrium oxide (Y2O3).

Abstract: A glass composition having a high Young's modulus and a low density is disclosed which can be mass-produced by a continuous process and easily made to have high surface smoothness. Also disclosed are a substrate including the glass composition and reduced in bending and resonance even upon high-speed rotation, a recording medium usable at a lower flying height, and an information recording device having a higher recording capacity and a shorter access time. The glass composition includes, in terms of mol %, 40 to 55% silicon dioxide (SiO2), 0.5 to 6% aluminum oxide (Al2O3), 2 to 20% lithium oxide (Li2O), 0 to 10% sodium monoxide ((Na2O), 2 to 30% R2O (R2O=Li2O+Na2O), 5 to 25% magnesium oxide (MgO), 0 to 25% calcium oxide (CaO), 0 to 10% strontium oxide (SrO), 10 to 40% RO (RO=MgO+CaO+SrO), 0 to 10% titanium dioxide (TiO2), and 0 to 5% zirconium oxide (ZrO2).

Abstract: A glass composition is disclosed which has a high modulus of elasticity (Young's modulus) and a high rigidity (modulus of elasticity/specific gravity) and is capable of being effectively inhibited from bending or vibrating. Also disclosed is a process for producing the glass composition. The glass composition comprises, in terms of mol %, 40 to 65% SiO2, 5 to 25% Al2O3, 2 to 20% Li2O, 0 to 9% Na2O, 0 to 10% TiO2, 0 to 10% ZrO2, 0 to 25% MgO, 0 to 25% CaO, and 0 to 10% SrO, provided that the content of RO (RO=MgO+CaO+SrO) is from 2 to 40% and the sum of (Li2O)/2 and Na2O is from 1 to 10 mol %, said glass composition further containing, as clarifiers, from 0.01 to 5 mol % SnO2 and up to 0.1 mol % sulfur (S) in terms of the amount of SO3.

Abstract: A glass-ceramics having a high elastic modulus, processes for producing the same, and an information recording medium substrate effectively inhibited from bending or vibrating are disclosed. The glass-ceramics has a major crystalline phase which has a Mohs' hardness of 6 or higher and is constituted of crystals containing manganese (Mn).

Abstract: A glass composition is disclosed which has a high modulus of elasticity (Young's modulus) and a high rigidity (modulus of elasticity/specific gravity) and is capable of being effectively inhibited from bending or vibrating. Also disclosed is process for producing the glass composition. The glass composition comprises, in terms of mol %, 40 to 65% SiO2, 5 to 25% Al2O3, 2 to 20% Li2O, 0 to 9% Na2O, 0 to 10% TiO2, 0 to 10% ZrO2, 0 to 25% MgO, 0 to 25% CaO, and 0 to 10% SrO, provided that the content of RO (RO=MgO+CaO+SrO) is from 2 to 40% and the sum of (Li2O)/2 and Na2O is from 1 to 10 mol %, said glass composition further containing, as clarifiers, from 0.01 to 5 mol % SnO2 and up to 0.1 mol % sulfur (S) in terms of the amount of SO3.

Abstract: A glass composition is disclosed which has a high modulus of elasticity (Young's modulus) and a high rigidity (modulus of elasticity/specific gravity) and is capable of being effectively inhibited from bending or vibrating. Also disclosed is a substrate for information recording media, which comprises the glass composition. The glass composition comprises the following components in terms of mol %: 50 to 64% SiO2, 6 to 18% Al2O3, 7 to 15% Li2O, 3 to 12% Na2O, 0 to 2% K2O, 0 to 10% TiO2, 0 to 4% ZrO2, 0 to 6% MgO, 0 to 9% CaO, and 0 to 6% SrO, provided that the content of RO (RO=MgO+CaO+SrO) is from 2 to 15%.

Abstract: A glass composition is disclosed which has a high modulus of elasticity (Young's modulus) and a high rigidity (modulus of elasticity/specific gravity) and is capable of being effectively inhibited from bending or vibrating. Also disclosed is a substrate for information recording media, which comprises the glass composition. The glass composition comprises the following components in terms of mol %: 40 to 60% SiO2, 8 to 25% Al2O3, 2 to 20% Li2O, 0 to 5% Na2O; provided that the content of R2O (R2O=Li2O+Na2O) is from 2 to 20%, 0 to 10% TiO2, 0 to 10% ZrO2, 5 to 25% MgO, 0 to 25% CaO and 0 to 6% SrO, provided that the content of RO (RO=MgO+CaO+SrO) is from more than 15 to 40%.