Provided are methods of forming a chemically strengthened glass-based article. Certain methods comprise: providing a glass-based substrate comprising a first surface and a second surface opposing the first surface defining a thickness (t), a length dimension, a width, and a weight; and ion exchanging a plurality of alkali ions into the glass-based substrate to form a non-zero alkali metal oxide concentration that varies along at least a substantial portion of the thickness (t). The ion exchanging comprises immersing a glass-based substrate in a molten salt bath comprising at least about 90% by weight KNO3, and less than about 10% by weight NaNO3 for a time in the range of 70% to 130% of the ion exchange time that produces a peak central tension (CT) with the same molten salt bath composition and temperature. Also provided are ion exchanged glass-based articles prepared by said methods.