Glass microbubbles include on an average weight basis: from 25.0 to 37.4 percent by weight of silicon; from 5.7 to 8.6 percent by weight of calcium; from 5.2 to 14.9 percent by weight, on a total combined weight basis, of at least one of sodium or potassium; from 0.3 to 0.9 percent of boron; and from 0.9 to 2.6 percent of phosphorus, wherein the weight ratio of phosphorus to boron is in the range of from 1.4 to 4.2, and wherein the glass microbubbles comprise less than 0.4 percent by weight of zinc. A raw product including the glass microbubbles, and methods of making the raw product are also disclosed.