NOVELTY - An alkali-free glass comprises 57-67.5 %mass silica, 17-25 %mass alumina, 1.7-5.5 %mass boric oxide, 2-8.5 %mass magnesium oxide, 1.5-8 %mass calcium oxide, 2-10 %mass strontium oxide, 0-1 %mass barium oxide, 0-2 %mass zirconia and 0-0.35 %mass chlorine, 0.01-0.15 %mass fluorine and 0.01-0.3 %mass tin, and has ( beta )-hydroxyl value of 0.15-0.60 mm-1, strain point of 680-735 degrees C, and average thermal expansion coefficient of 30x 10-7-43x 10-7/ degrees C at 50-350 degrees C. The temperature (T2) at which the glass viscosity reaches 102 dPa.second is 1710 degrees C or less.    USE - Alkali-free glass is used for substrate for magnetic disk, display board, photomasks and solar cell.    ADVANTAGE - The alkali-free glass has excellent float moldability.    DETAILED DESCRIPTION - An alkali-free glass comprises 57-67.5 %mass silica, 17-25 %mass alumina, 1.7-5.5 %mass boric oxide, 2-8.5 %mass magnesium oxide, 1.5-8 %mass calcium oxide, 2-10 %mass strontium oxide, 0-1 %mass barium oxide, 0-2 %mass zirconia and 0-0.35 %mass chlorine, 0.01-0.15 %mass fluorine and 0.01-0.3 %mass tin, and has ( beta )-hydroxyl value of 0.15-0.60 mm-1, strain point of 680-735 degrees C, and average thermal expansion coefficient of 30x 10-7-43x 10-7/ degrees C at 50-350 degrees C. The temperature (T2) at which the glass viscosity reaches 102 dPa.second is 1710 degrees C or less. The temperature (T4) at which the glass viscosity reaches 104 dPa.second is 1330 degrees C or less. The total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is 12-21 %mass. The ratio of magnesium oxide with respect to the total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is more than 0.2. The ratio of calcium oxide with respect to the total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is less than 0.50. The ratio of strontium oxide with respect to the total content of magnesium oxide, calcium oxide, strontium oxide and barium oxide is less than 0.60. An INDEPENDENT CLAIM is included for manufacture of alkali-free glass.