Abstract: There is provided a glass substrate for observing minute substance, made of porous glass and capable of separating and capturing a minute substance with a 10 to 500 nm average particle diameter contained in a solution or a suspension, comprising a porous glass substrate having a plurality of pores, wherein the plurality of pores has an average pore diameter ranging from 30 to 110% of the average particle diameter of the minute substance, each of the plurality of pores has a surface pore diameter on an uppermost surface of the glass substrate, a standard deviation of the surface pore diameter is 60% or less of the average particle diameter of the minute substance, and a pore with a pore diameter ranging from 60 to 140% of a pore diameter at peak top in a pore diameter distribution of the plurality of pores occupies 90% or more of total pore volume.

Abstract: A glass substrate for a CdTe solar cell includes a base composition includes, in terms of mol % on a basis of following oxides: from 60 to 75% of SiO2; from 1 to 7.5% of Al2O3; from 0 to 1% of B2O3; from 8.5 to 12.5% of MgO; from 1 to 6.5% of CaO; from 0 to 3% of SrO; from 0 to 3% of BaO; from 0 to 3% of ZrO2; from 1 to 8% of Na2O; and from 2 to 12% of K2O, wherein MgO+CaO+SrO+BaO is from 10 to 24%, Na2O+K2O is from 5 to 15%, MgO/Al2O3 is 1.3 or more, (2Na2O+K2O+SrO+BaO)/(Al2O3+ZrO2) is 3.3 or less, Na2O/K2O is from 0.2 to 2.0, Al2O3??0.94MgO+11, and CaO?0.48MgO+6.5.

Abstract: A glass substrate for a CIGS solar cell containing specific amounts of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, ZrO2, TiO2, Na2O and K2O, respectively. The glass substrate satisfies the specific requirements regarding MgO+CaO+SrO+BaO, Na2O+K2O, MgO/Al2O3, (2Na2O+K2O+SrO+BaO)/(Al2O3+ZrO2), Na2O/K2O, the relation of Al2O3 and MgO, and the relation of CaO and MgO, respectively. The glass substrate has a glass transition temperature of 640° C. or higher, an average coefficient of thermal expansion within a range of 50 to 350° C. of 70×10?7 to 90×10?7/° C., the temperature (T4) of 1,230° C. or lower, the temperature (T2) of 1,650° C. or lower, and a density of 2.7 g/cm3 or less. The glass substrate satisfies the relationship of T4?TL??30° C.

Abstract: A glass substrate for a Cu—In—Ga—Se solar cell. The glass substrate contains specific oxides with the specific amounts, respectively. The glass substrate has a glass transition temperature of from 650 to 750° C., an average coefficient of thermal expansion within a range of from 50 to 350° C. of from 75×10?7 to 95×10?7/° C., a relationship between a temperature (T4), at which a viscosity reaches 104 dPa·s, and a devitrification temperature (TL) of T4?TL??30° C., a density of 2.6 g/cm3 or less, and a brittleness index of less than 7,000 m?1/2.