Poly(diorgano/organohydrogen)siloxane copolymers

A method comprising:

• 1) Combining starting materials comprising
• A) a source of siloxane units of formula (R2SiO2/2),
• B) a source of siloxane units of formula (RHSiO2/2),
• where each R is independently selected from the group consisting of a monovalent hydrocarbyl group and a monovalent halogenated hydrocarbyl group, and
• C) an acid catalyst,
• thereby forming a mixture;
• 2) Agitating the mixture at a temperature of 20° C. to 110° C., thereby forming a reaction mixture comprising the poly(diorgano/organohydrogen) siloxane copolymer via equilibration reaction;
• 3) Using a vibrational spectroscopy technique selected from the group consisting of infra-red spectroscopy and Raman spectroscopy to monitor a spectral region including an absorbance band that corresponds to one or both of a concentration of decoupled (RHSiO2/2) and a concentration of coupled (RHSiO2/2) units in the reaction mixture;
• 4) Stopping the equilibration reaction when a target related to the absorbance band is reached, where the target is a rate of change of the absorbance band height or a rate of change of the absorbance band area, and the rate of change has a value of 0% to 10% of its maximum absolute value measurable during the course of the equilibration reaction, thereby preparing a a poly(diorgano/organohydrogen) siloxane copolymer;
• and
• adding the poly(diorgano/organohydrogen) siloxane copolymer as a crosslinker to a curable silicone formulation.