An amino alkoxy-modified silsesquioxane (AMS) comprising one or more compounds selected from the group consisting of an amino AMS, an amino/mercaptan co-AMS, an amino/blocked mercaptan co-AMS, mixtures thereof, and a weak acid-neutralized solid or aqueous solution thereof, and a method of making the amino AMS, are presented. The compounds are useful in compounding, processing, cure and storage of silica-reinforced rubbers because they contain low levels of volatile organic compounds (VOC).